Impedance Control isn't functional for non-direct drive actuators.

[shreyhas]

🐛 Bug Report

Impedance control causes instability in non-direct drive dephy actuators when current gains are not set. Any value of k & b gains (including 0) causes instability, even when setting motor_output_position to its current position.

🔬 How To Reproduce

Steps to reproduce the behavior:

1. Run impedance_control.py with default ki, kp and any values of k & b.
2. Run impedance_control.py with kp = 10, ki = 5. No instability will be noticed.

Environment

Raspberry Pi 5 with Ubuntu with a real-time kernel.