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1. Page 7 of 11 Application Note QCI AN031 QuickSlver Controls Inc Original Function 1 2 1 FOSS p e ee 0 8 x c 0 6 S t o 0 4 o2 st tee 0 ooo i i Peeeg 0 3 14 6 28 Time Seconds Figure 6 Desired Position Profile From this data successive derivatives should be taken to obtain velocity and acceleration data for the original profile This can be done in Excel or another spreadsheet program as shown in Table 2 on the next page Pos revs Time sec dx revs dt sec Vel rps Acc rps s 0 5 0 5 cos time me ee pos pos time time dx dt vel vel dt 0 0 0 0 0 007885285 0 1256636 0 00789 0 1257 0 06 0 99081 0 031416786 0 2513272 0 02353 0 1257 0 19 0 967309 0 070223397 0 3769908 0 03881 0 1257 0 31 0 928554 0 123693115 0 5026544 0 05347 0 1257 0 43 0 875154 0 190982694 0 628318 0 06729 0 1257 0 54 0 807953 Table 2 Example Velocity and Acceleration Spreadsheet Note The value n 25 is chosen for 50 point resolution use larger values of n for higher resolution Velocity and acceleration data can be plotted against time to verify data integrity Since the derivative of position yields velocity and the derivative of velocity yields acceleration these plots should be visually examined to verify correct velocity and acceleration calculations In this case the choic2. e Third is acceleration 1073741824 773094 212278758 e Fourth is the ending velocity of that a goeea oa s SoA 912278758 1073741824 773094 189085935 segment 1073741824 773094 0 1073741824 773094 189085935 ee 161000 773094 189085935 This data table will feed the IMS command 161000 773094 189085935 one line at a time one velocity segment at a time until the entire velocity profile is Figure 2 Ode to Joy Data Text File executed Parameters of the Data Table Time 0 to 2 147 483 6471 Indicating the number of time ticks 120 usec time slices to count down before loading the next set of data Note that the time parameter does not influence the motion profile it acts as a time delay giving the profile enough time to develop based on the acceleration and velocity data If this value is too small the segment will end prematurely too big and the segment will run on for longer then intended A 0 indicates the last set of data to be transferred and tells the QCI device to exit the IMS operation In this application the values chosen for segment times are indicative of note length but their corresponding parameters velocity and acceleration are calculated from the constant acceleration kinematics equations of motion to make the song Ode to Joy Time Conversion ticks to seconds 270 ticks x 00012 0324 sec tick 3470 ticks x 00012 4164 sec tick Position 2 147 483 648 to 2 147 483 647 Unless the
3. Application Note QCI AN031 QuickSilver Controls Inc Date 12 November 2004 www QuickSilverControls com Interpolated Motion Control Standalone Associated Files Profile Playback Ode to Joy qcp Profile Playback Ode to Joy txt Profile Playback Position t qcp Profile Playback Position t txt Make IMS Segment xls Introduction For many industrial camming applications it is necessary to define a motion profile with velocity segments The Interpolated Motion feature allows users to execute interpolated movements by utilizing four Data Registers that cycle through Time Position Acceleration and Velocity Data See Interpolated Motion Control in SilverLode User Manual for a general description These registers define constant acceleration velocity segments that ramp up or down to a desired velocity or move at a constant velocity acceleration 0 over a period of time By streaming data through these registers the IMS command can interpolate the points in each velocity segment as well as between the velocity segments to create a continuous complex motion profile The cycling of data can be accomplished either by a host that streams the data to the device via serial communication or by the device operating in a standalone configuration This document will focus on standalone interpolated movement where all data resides in the QCI device s non volatile memory and is spooled to the IMS command via a Register File Array comm
4. QCI AN031 QuickSlver Controls Inc entire Register File Array This loop checks to see if the segment data just loaded has been used then queues the next row of data into the same four registers If the next segment is not loaded into data registers before the previous segment ends the IMS command uses the acceleration value in Register 19 to come to a stop and exits IMS operation Checking for Stale Data Register 17 is an operational register for the IMS command and contains the register reference number of the first register that is loaded with segment data Once the IMS operation copies the segment data it writes a 1 to the upper word of Register 17 indicating the data is stale When fresh data is loaded Register 17 must have the register reference number rewritten in order to clear the upper word OOOOXXXX and once the data is stale the IMS operation automatically writes a 1 to the upper word O001XXXxX in Ode to Joy XXXX is 001E 30 in hex A single Jump on Register Equals JRE command back to itself when Register 17 indicates fresh data is present Reg17 0000001E can serve as a single line checking routine As soon as the 1 is written to the upper word the jump condition is no longer valid and the loop moves on to the next task Queuing the Next Row of Data Once the previous segment is stale the loop needs to load with the RLM command the next row of data into the segment data regis
5. Register File array Each row contains an IMS velocity segment Creating a Data Table for Use with IMS EPER name profi Te od to Just as in the Ode to Joy example a data table 10427 167558182 1010645 can be made and linked to a QCP file The data 6a53138 for this application can be copied directly out of 19259671 the spreadsheet and pasted in to the txt file 14104615 15968611 Notice that the 50 row has a few extra ticks EEE added for any rounding errors that may have built 14965256 up and the position is set as the desired stopping 7 11733159 position of the profile as described earlier Also note that an extra row the 51 with a 0 for time has been added with repeated parameters for position velocity and acceleration The 0 for time initiates an exit from IMS operation a very important step if this is the desired action 11733188 10259736 8624482 6853216 4973870 1073741808 1914 3016083 Q Q Q Q 1010731 Figure 9 Position Data Text File QuickSilver Controls Inc Page 10 of 11 Application Note QCI AN031 QuickSlver Controls Inc Make IMS Segments The Make IMS Segments xls spreadsheet example uses time data in 11 25 increments column B Fora more precise approximation use smaller fractions of tr for the time interval this will also require more data points Position is a cosine function of time column A and that is why time increments were chosen as a fraction of Tr Increase
6. and Two specific application examples are provided in this application note one that details using velocity over time data ode to joy and another that details position over time data sinusoidal motion Velocity over Time Data Ode to Joy Example The easiest and most straightforward way to understand IMS is within an application where the data is defined by velocity as a function of time as in the Ode to Joy example In this application moves of different velocities create musical notes and the duration of the note is defined by how long the servo maintains that velocity The velocity profile is defined so that it ramps up or down to specific velocities that coincide with the musical notes of Ode to Joy Property of QuickSilver Controls Inc Page 1 of 11 This document is subject to change without notice QuickControl is a registered trademark of QuickSilver Controls Inc Other trade names cited are property of their explicit owner Application Note QCI AN031 QuickSlver Controls Inc Velocity Profile Velocity cps Time s Figure 1 Ode to Joy Velocity Profile As shown in Figure 1 each velocity segment corresponds to a musical note C D E F or G The actual velocities that correspond to musical notes are shown in Table 1 To find the number of individual velocity segments 21 that must be sent to the IMS operation the entire profile is parsed up into segments that ramp an
7. d play notes and segments that ramp to zero velocity for pauses Note Velocity cps Velocity SVU G 31360 252544077 F 27960 225163660 E 26360 212278758 D 23480 189085935 C 20920 168470092 Table 1 Musical Scale cps counts per second from the servo with a 4000CPR encoder SVU native SilverLode Velocity Units see Scaling in User Manual QuickSilver Controls Inc Page 2 of 11 Application Note QCI AN031 QuickSlver Controls Inc Creating a Data Table for Use with IMS The Register File System within QuickControl revision 4 0 permits the linking of text files that contain data to be used by the IMS command io x File Edit Format Help Profile Playback Register File Array Figure 2 shows a Register File Array consisting of 22 rows and 4 columns Each Each row contains an IMS velocity segment NVRegd rray name Profile ode to Joy row 22 col 4 row specifies an IMS velocity segment 3470 1073741824 773094 212278758 1073741824 773094 0 Each column contains one of the four IMS 1073741824 773094 212278758 1073741824 773094 225163660 parameters 1073741824 773094 252544077 1073741824 773094 0 1073741824 773094 252544077 e First parameter is time in servo lors eek AEs Soe ee f 1073741824 773094 189085935 cycle clock ticks 1073741824 773094 168470092 ae 1073741824 773094 e Second is position 1073741824 773094 168470092 wae 1073741824 773094 189085935
8. e of cosine for the original function makes visual inspection of successive derivatives easy QuickSilver Controls Inc Page 8 of 11 Application Note QCI AN031 QuickSlver Controls Inc d dt Original Function 1 5 1 q Z 0 5 D 0 8 5 05 gt 1 1 5 0 3 14 6 28 Time seconds Figure 7 Velocity Profile d x dt Original Function o oa a a Acceleration RPS S O as oo 4 3 14 6 28 Time Seconds oO Figure 8 Acceleration Profile QuickSilver Controls Inc Page 9 of 11 Application Note QCI AN031 QuickSlver Controls Inc Creating Data Segments for IMS Interpolated Move segments can also be computed within a spreadsheet from the actual position velocity acceleration and time data Following the rules for each parameter an IMS table is generated below Interpolated Move Acceleration Velocity Segments SAU SVU We IC KS ee osmonkcounts E a eae T dt 0 00012 poScurrentt1073741824 acc 3865 47056 vel 32212254 705 1047 1073741824 1914 1010645 1047 1073741840 1869 3015999 1047 1073741888 1794 4973788 1047 1073741966 1691 6853138 1047 1073742073 1561 8624410 Table 3 IMS Data Segments Defined in Spreadsheet See Make IMS Segments below for an explanation of the XLS file 47 Profile Playback Position t Notepad i 10j x Eile Edit Format Help Profile Playback
9. each parameter used by IMS A slight gain 10 or lower is added to the acceleration and velocity data These gains need to be equal or else the ending position of the profile is negatively affected The gains are used to increase the peak position of the COS curve With the original calculated values the actual position curve falls short of the peak value Important Notes Interpolated time is in SilverLode servo clock ticks dt 120usec and is rounded down to the nearest integer It was noted that this along with rounding interpolated velocity and acceleration up yields precise moves most of the time stopping exactly on 0 and oscillating 1 count Interpolated position is NOT the position each segment is commanded to it is only used to project the move in a direction IMS position is defined to be current position 1073741824 if actual velocity is in the positive direction or 1073741824 if actual velocity is in the negative direction See the Interpolated position graph and the IF statement in the cell formatting Interpolated velocity and acceleration are scaled absolute values they do not need a sign because the position parameter will be projecting the direction of the segment See the Interpolated plots and cell formatting for constants used QuickSilver Controls Inc Page 11 of 11
10. ed but will not On ce th e d ata ta b eis be updated at download created it must be Delete Select File to Import Add Registe r LINK If Link is checked the selected file will be downloaded into non volatile memory on every download of Profile Playback Ode to Joy qep IV Link file to program at download Import Register File gt Profile Playback Ode to Joy txt Select File to Link D 7 ata From Text File Note The selected file needs to be in the same directory as Profile Playback Ode to Joy qep Figure 3 Register file Dialoque Windows Select Register File Arrays under Display and click on the Import Register File Data From Text File button The text file that is being linked to the QuickControl program must be saved to the same folder as the QuickControl program QuickSilver Controls Inc Page 5 of 11 Application Note QCI AN031 QuickSlver Controls Inc Configuring the QuickControl Program to use the Register File System Once the text file is linked the QuickControl Program Edit Write Register fie O O O O OO OoOo x needs to access the register file properties so that it can BK iterate through the entire array Three Write Register GA File WRF commands are needed to do this The first FE NOE a WRF command writes the non volatile memory Start Profile Odetoly Address where the first row of data resides to a user Regitier Fie Anaye Register Fi
11. ers The four user registers are defined by the value in Register 17 The first holds the time data the second position data xl the third acceleration data and the fourth register holds velocity data In Profile Playback Ode to Joy qcp these E Cancel are Registers 30 34 Profile Ode to Joy Description After the operational registers are loaded with data and the __ __Batfesiterfle idie four segment data registers are identified they should be Select the Starting Register cae loaded with the first row of segment data from the Register User 30 eee File Array This is accomplished via indirect addressing and shares reds the Register Load Multiple RLM command With the eel ag ee Bane Indirect Addressing Mode checkbox checked the RLM ban command uses the value in the Accumulator 10 as the Normal starting non volatile memory address of the data to be E me C Native loaded into the segment data registers Therefore before the RLM is issued the Start Address from the first WRF must be copied into the Accumulator 10 Then the RLM is issued loading registers 30 34 with time position acceleration and velocity data Figure 5 RLM Dialog window After the first segment is queued into the data registers the IMS command starts execution The IMS command requires two tasks running in a loop to ensure that it can iterate through the QuickSilver Controls Inc Page 6 of 11 Application Note
12. es register The register file system assigns the start address automatically upon linking to ensure that the entire table will fit in non volatile memory The second a l WRF command writes an Address Increment to another C register The register file system assigns an address increment based on the number of columns reported col 4 see Figure 2 in the first line of the Register File Figure 4 WRF Dialogue Array The third WRF command writes the Number of Rows in the array to a third register Specified in the first line of the Register File Array row 22 see fig 2 See Register File System in SilverLode User Manual for details Write To Register Configuring the IMS Command within the QuickControl Program Once three user registers contain the Start Address Address Increment and Number of Rows of the table the IMS command has to start iterating through the data The IMS command uses seven registers in its operation Register 17 contains a data indicator see Checking for Stale Data in the upper word and the register reference number of the first user register that is loaded with segment data in the lower word Register 18 is used internally to hold the segment time countdown Register 19 holds a data loss deceleration value This value will only be used if there is an under run of data to the IMS operation the time value counted down in Register 18 reaches zero before a new velocity segment is loaded into the user regist
13. ion value is left at 1073741824 Time decrements down in register 18 as described above Data in 21 Row ramp to stop 272 161000 773094 189085935 This segment ramps down to a stop using the standard acceleration after completing the final D note Give a few extra ticks than calculated 270 2 to allow for any rounding errors that have built up over the profile Since the segment is commanding a stop give the desired stopping position 161000 rather than 1073741824 and starting velocity 189085935 rather than the ending velocity 0 of the segment Time decrements down in register 18 as described above Data in final Row 0 161000 773094 189085935 This segment has a 0 for time indicating that it is the last segment of the profile and commands the device to exit IMS operation Simply repeat position acceleration and velocity parameters as they will have no effect linked to the QuickControl program that uses it This is accomplished with the Programs gt Register Files option in the main toolbar x Li n ki ng the Data Non volatile Register File System x 5 Table with the Con i i Cancel ONE TIME IMPORT Reg l ste r F l I e a One Time Import will download the selected file into non volatile memory one time The Register File s and data will remain with Syste m Profile Ode to Joy Profile Playback Ode to Joy qep 7 Properties and in non volatile memory until changed or delet
14. r is intended to allow the acceleration and velocity parameters to define the shape of the profile while position is projected off to some unattainable position Data in Row 1 ramp and play E 3470 2147483647 773094 212278758 The 3470 ticks of time data are copied to register 18 just before this segment s execution This count is decremented every servo cycle 120 usec until it reaches 0 If register 17 has been written to it should contain the register reference number of the first register out of four user registers from which to load data If register 17 still has a 1 in the upper word the IMS QuickSilver Controls Inc Page 4 of 11 Application Note QCI AN031 QuickSlver Controls Inc operation will use the value in register 19 to stop motion and exit IMS operation See the Configuring the IMS Command within the QuickControl Program section of this application note for a complete discussion Velocity segments are defined in this manner throughout the song Note that when a double note is played the two notes are not defined as a single long note but two distinct notes with a quick ramp down to 0 velocity and back up again This is done to maintain the beat of the original tune If the double notes are profiled as a continuous note the tune reduces to ten beats rather then fifteen Data in Row 2 ramp to zero velocity 270 1073741824 773094 0 This segment ramps down to zero velocity but does not stop the posit
15. segment is intended to come to a halt at a given location the position parameter is only used to project the direction of motion It should be noted that position calculations incorporate register wrap around as they are summed For a general move use the present position plus or minus 1 073 741 824 This value is large enough to project moves properly while remaining small enough to never wrap around the register range and project movement QuickSilver Controls Inc Page 3 of 11 Application Note QCI AN031 QuickSlver Controls Inc in the opposite direction If the segment should stop decelerate to zero velocity give the desired ending position of the move In this case the position parameter is used to direct the motion profile to a specific location Note that in Figure 2 all but two position parameters are large positive values to project each velocity segment out to infinity The 21 segment commands a decelerating stop from the last D velocity so the final stopping position is given The gon segment has a 0 for time commanding an exit from IMS and indicating it is the last segment Since they have no effect the previous position velocity and acceleration parameters are repeated Acceleration 1 to 1073741823 Scaled from a 0 2000RPM 120usec value This parameter has the highest priority and defines the acceleration or deceleration used in reaching the ending velocity of the segment A 0 indicates a constan
16. t velocity segment Acceleration is calculated from time using constant acceleration kinematics equations of motion See SilverLode Acceleration Units SAU in User Manual for scaling details Acceleration Conversion With 4000CPR Encoder cps s to a SAU 2 lrev 3865 47056 gt x 800000 x _ ___ 773094 a sec 4000 counts Velocity 0 to 2 147 483 647 Scaled from a 0 4000RPM value Unless the segment is the last of the profile this should be the desired ending velocity of the segment When specifying the last segment of a profile set velocity equal to the starting velocity of the segment Do not set it to the ending velocity of the segment usually 0 this will cause the servo to undershoot the desired ending position See SilverLode Velocity Units SVU in User Manual for scaling details The musical scale shown in Table 1 define the velocities used which are given by Velocity Conversion With 4000CPR Encoder cps to a SVU 32212254 7 Sx 31360 sams x7 _ 959544077 4000 counts Explanation of the Data Table The first row of the Register File Array shows a velocity segment that ramps up to the E note velocity and projects that movement for 3470 ticks 0 4164 sec before looking to load a new segment or decelerate to a stop using register 19 Note that these parameters define the initial ramping and constant velocity segments while the position specified for this segment is never reached The position paramete
17. ters To achieve this the current Start Address must be added to the Increment Address the resulting sum is the Start Address of the next row of data in the Register File Array This is the new value that must be copied into Accumulator 10 before the RLM command executes Note See the CHECK loop in Profile Playback Ode to Joy qcp for an example of this routine This loop should iterate through the entire Register File Array with no problems Similar routines can be implemented for use with the IMS command but care should be taken to ensure that they execute in a timely manner If the loop is trying to do too many tasks in between checking for stale data and loading the new data a data under run could occur causing the interpolated move to decelerate to a stop using Register 19 and exit prematurely If it is necessary to repeat the profile or exit the program after the profile is finished use the Calculation CLC command to decrement the Number of Rows register each time the loop executes and use the JRE command when that register contains a 0 to jump to an exit line or repeat the process Position Over Time Data Sinusoidal Motion Example In this example position vs time data for a cosine function will be used to create a table to follow the cosine curve Figure 6 shows the original position function defined by an inverted cosine function shifted for positive displacement over t 0 to t 27 QuickSilver Controls Inc
18. the fraction to 11 50 to yield a much better approximation The encoder constant D2 only applies to scaled position data position in counts columns G amp H and the final position column for the IMS segment column N Columns F K use the finite difference between time and position to generate velocity dx dt and acceleration dx dt data Columns J amp K are plotted against time for the velocity and acceleration plots respectively A COS function for position was chosen because successive derivates velocity and acceleration are easily identified vel SIN and acc COS see the first three plots Note that the start and end points of actual velocity dx dt and acceleration d x dt are hi lighted in red This is to indicate that the endpoints of dx dt can cause a spike in d x dt and in some instances needs to be inputted manually rather then calculated by the spreadsheet It was noticed that adjustments to these endpoints were needed to realize a more precise move final position 1 count around 0 If the actual acceleration plot was let to begin and end on 1 as it should the final position was short 30 counts or so Once the position function and it s successive derivatives are confirmed graphically compute the actual IMS data segments cols M P Click on a cell in columns M P to see the constants used to scale actual position velocity and acceleration data into Native SilverLode Units based on the register range for
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