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controlgains [2019/10/07 15:48]
jfduval
controlgains [2020/12/07 19:43] (current)
lmooney [Typical Values]
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 ====== Control Gains ====== ====== Control Gains ======
  
-<color #​ed1c24>​Important: ​the controllers ​have been reworked in 2018Their internal dividers have been changed ​and they now use 10x bigger gainsIf you are using old firmware do not try the gains listed below!</​color>​+Over the years we have been doing considerable improvements to our control algorithmsAs our clients push the limits of what can be done with the system we learn and adaptAs a result, the recommended gains depend on the firmware version ​you are using. Please make sure to follow ​the correct section.
  
-The right gains depend on your application and your system. The values listed below are only provided as an example to give you an idea of the range. Use them for 2018systems.+The right gains depend on your application and your system. The values listed below are only provided as an example to give you an idea of the range. 
 + 
 +===== Latest (v4.1+) ===== 
 +{{ ::​consbar.gif |}} 
 + 
 +=== Firmware: === 
 +Use this information ​for releases greater or equal to 4.1. 
 + 
 +In this version, our controllers'​ stability is improved near the maximums. Also, there'​s now a feed-forward (ff) gain for the commands and controllers. For ff, 0 is 0% and 128 is 100%. 
 + 
 +The current units were updated to reflect the Q-axis current in Field Oriented Control. As such, their magnitude is now 38% of their earlier units. This leads to a redefinition of the torque constant since Kt = unit torque per unit current. 
 + 
 +An older controller that commanded 10 Amps during a phase of the gait, now would just need to command 3.8 Amps. 
 + 
 +==== Typical Values === 
 + 
 +These values are used in out controller settings and result in a safe operation. Use them as a starting point to adjust the gains of your specific application. 
 + 
 +Note that setting the Feed Forward gain (ff) to **128** may cause instabilities in certain scenarios. Only increase it if the performance is really needed.  
 + 
 +=== Current === 
 + 
 +  * Proportional gain (kp) : 250 
 +  * Integral gain (ki) : 200 
 +  * Differential gain (position control only, kd) : 0 
 +  * Stiffness (impedance control only, K) : 0 
 +  * Damping (impedance control only, B) : 0 
 +  * Feed Forward gain (ff) : 100 
 + 
 +=== Position === 
 + 
 +  * Proportional gain (kp) : 175 
 +  * Integral gain (ki) : 50 
 +  * Differential gain (position control only, kd) : 0 
 +  * Stiffness (impedance control only, K) : 0 
 +  * Damping (impedance control only, B) : 0 
 +  * Feed Forward gain (ff) : 0 
 + 
 +=== Impedance === 
 + 
 +  * Proportional gain (kp) : 200 
 +  * Integral gain (ki) : 200 
 +  * Differential gain (position control only, kd) : 0 
 +  * Stiffness (impedance control only, K) : 0 - ? 
 +  * Damping (impedance control only, B) : 0 - 4200 
 +  * Feed Forward gain (ff) : 32 
 + 
 +=== Physical Correlations === 
 + 
 +  * Motor velocity units: 400 x motor clicks per ms 
 +  * Impedance Setpoint: motor clicks 
 +  * Motor Position: motor clicks 
 +  * Motor click: 16383 per full rotation 
 +  * Damping Current (mA) = - B * Motor Velocity * 0.0000625 
 +  * Spring Current (mA) = K * ( Impedance Setpoint ​ -  Motor Position) * 0.00078125 
 +  * Commanded Current (mA) = Spring Current ​Damping Current 
 +  * Motor Torque (mNm) = Commanded current * 0.146 
 + 
 +For additional information about units, please see the [[units|Data,​ Units & Conversion Formulas]]. 
 + 
 +===== 2018 to late 2020 (v4.0) ===== 
 + 
 +**Summary of changes:** the controllers have been reworked in 2018. Their internal dividers have been changed and they now use 10x bigger gains. If you are using pre-2018 firmware do not try the gains listed in this section! 
 + 
 +**Firmware:​** use this for releases lower or equal to 4.0. For 4.1 and above jump to the next section.
  
 === Current: === === Current: ===
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   * K & B values will depend greatly on your application,​ the values above are simply a starting point.   * K & B values will depend greatly on your application,​ the values above are simply a starting point.
   * [[actpackplan|Visual demonstration available here]] (bottom of the page)   * [[actpackplan|Visual demonstration available here]] (bottom of the page)
 +
 +===== Before 2018 =====
 +
 +This is not supported anymore. Use the gains we gave you then, and please consider upgrading to current firmware.
 +
  
  
controlgains.1570463293.txt.gz · Last modified: 2019/10/07 15:48 by jfduval