运动控制器加减速过程的冲击限制参数及使用方法
2023-10-17 21:42阅读：
在调试过程中怎样使用Jerk 参数的相关描述：
The Requested Jerk parameter is used for point-to-point and
velocity closed loop motion commands. The term 'jerk' is the rate
of acceleration. The Requested Jerk specifies the requested average
Target Jerk. Therefore, the peak Target Jerk will be 1.5 times the
Requested Jerk.
Jerk参数是加速度的变化率。因为它是个平均值所以峰值的加速度变化率是jerk参数的1.5倍。
The Requested Jerk parameter is used as follows:
- Specify the Target Type (RMC75/150 only, firmware 1.50 and
newer)
If the Requested Jerk is set to a non-zero number, the target
generator will generate speed profiles with s-curves. If the
Requested Jerk is set to 0, the target generator will generate
trapezoidal target speed profiles. Notice that the value of the
jerk doesn't matter when specifying a target type, only non-zero
versus zero.
Jerk值不为零将被指定为S速度曲线。
Notice that the RMC200 has a separate Target
Type parameter for selecting trapezoidal or s-curve speed profiles.
- Speed at Position (36) Command
The Requested Jerk is used in the calculation of the speed at
position command when the S-curve target generator is active.
The Requested Jerk is used in the calculations for
point-to-point moves when the following criteria are
met:
- The target is stopped but not at the final position.
- The requested velocity is non-zero (as it usually is unless the
user wanted to just stop at the current position).
- The distance to move is less than the acceleration distance
plus deceleration distance.
- 加速过程没有结束就需要减速的小行程运动，Requested Jerk 参数才起作用（青岛客户问题）
S-Curve Target Profile
The S-curve profile generates a 5
th-order profile for
the Target Velocity during the acceleration and deceleration
phases, as shown by the magenta line below. This results in a
smooth Target Acceleration (gray line), with no sudden jumps. A
smooth Target Acceleration will result in a smooth control output
contribution by the Acceleration Feed Forward, for optimal control
of the axis motion.
With the S-curve target profile, the commanded acceleration
specifies the
average Target Acceleration. The maximum
instantaneous Target Acceleration will be 1.5 times the commanded
acceleration.
![]( "运动控制器加减速过程的冲击限制参数及使用方法")
A disadvantage of the RMC's S-curve target profile is that if
another motion command is sent to the axis during the deceleration
portion of a point-to-point command, the Target Acceleration will
be reset to zero before continuing. This will extend the
deceleration time and may cause the Target Position to overshoot
the requested position, as shown below. If commands are
continuously sent to the axis while commands are in progress, Delta
recommends using the trapezoidal target profile instead. Notice
that if an identical command is sent during the deceleration
portion, the RMC will recognize this and not reset the Target
Acceleration, and the axis will not overshoot.
![]( "运动控制器加减速过程的冲击限制参数及使用方法")
Trapezoidal Target Profile
The Trapezoidal profile generates linear segments for the Target
Velocity, as shown by the magenta line below. This results in a
Target Acceleration (gray line), that suddenly jumps to its
requested value. This will result in a sudden jump in the control
output contribution by the Acceleration Feed Forward, and may
prevent optimal control of the axis motion, especially for highly
dynamic systems.
A trapezoidal target profile should be used if commands are
continuously sent to the axis while commands are in progress, to
prevent the target position from overshooting.
如果对上述问题感兴趣，随时联系 slsheng@163.com
![]( "运动控制器加减速过程的冲击限制参数及使用方法")
