can the force movement be same speed instead of same time period

Hi Jinyang, If I understand correctly, you are using the position controller and you would like to make movements of a certain constant velocity? If that is your question, then yes you can make the position controller move at a constant velocity. In the example code for the position controller the duration of the movement is relatively constant (though not perfectly). In order to make the movement have a constant velocity you will need to plan the trajectory differently. You will need a ramp up to your required velocity, constant speed, ramp down to zero. The general principal using Stateflow is: 1. Create a ramp up state. x, y in the trajectory is previous x, y + new calculated position based on current velocity. Add to the current velocity. When at the desired velocity move to the next state 2. Create a steady speed state x, y in the trajectory is the previous x,y + new calculated position based on desired velocity. When you reach the threshold position to begin deceleration move to the next state. 3. x, y in the trajectory is previous x, y + new calculated position based on current velocity. Subtract from to the current velocity. When the final position is reached you should be at zero velocity, stop movement. Please let me know if that helps. Duncan

Hi Jinyang, Yes, that is where the changes should go. All the best, Duncan