Can force/torque control of joint achieve positive and negative motion during one control loop?

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biscuit122
Posts: 19
Joined: 23 Jan 2018, 16:16

Can force/torque control of joint achieve positive and negative motion during one control loop?

Post by biscuit122 » 05 Nov 2018, 02:46

In this tutorial, I set a sin function to define a joint force control. But it only move in one direction, so if I do not change target velocity, do you have method to move joint in two direction during one control loop? https://github.com/feig122/force_test

coppelia
Site Admin
Posts: 6800
Joined: 14 Dec 2012, 00:25

Re: Can force/torque control of joint achieve positive and negative motion during one control loop?

Post by coppelia » 07 Nov 2018, 08:02

Hello,

you can only set the amplitude of the force/torque. The sign is set via the joint target velocity. So set following:

Code: Select all

sim.setJointForce(handle,math.abs(f))
if f~=0 then
    sim.setJointTargetVelocity(handle,math.abs(vel)*f/math.abs(f))
end
Cheers

biscuit122
Posts: 19
Joined: 23 Jan 2018, 16:16

Re: Can force/torque control of joint achieve positive and negative motion during one control loop?

Post by biscuit122 » 07 Nov 2018, 20:37

coppelia wrote:
07 Nov 2018, 08:02
Hello,

you can only set the amplitude of the force/torque. The sign is set via the joint target velocity. So set following:

Code: Select all

sim.setJointForce(handle,math.abs(f))
if f~=0 then
    sim.setJointTargetVelocity(handle,math.abs(vel)*f/math.abs(f))
end
Cheers
Thanks for your brilliant tutorial, which helps me a big deal!

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