CDHD2 Servo Drive Force Control

New Feature: Position Controlled by External Force Sensor

Force Control

Continuous technological developments in Surface Mount Devices (SMD) and high precision Pick & Place applications, introduce new challenges for the motion control industry. Such applications require a precise control of the applied force or torque. Unlike traditional “current limit” methods, which depend to motor parameters and are subjected to temperature and manufacturing tolerances, the combination of a motor feedback and an external force sensor, provide superior position – force control for high-end OEM applications. SERVOTRONIX’S CDHD2 servo drive supports Real-Time force control together with advanced position control algorithms.

Key benefits

  • High Force Control performance.
  • PI Force controller – Increased smoothness and High control against overshot.
  • Compatible with SERVOTRONIX’s proprietary HD controller and Linear controller.

Figure 1. Cascade Control System with Force Controller

Application examples

Best suited for force sensing applications such as:

  • Screws tightening applications, where a precise torque on screw is required.
  • Wires production.
  • Test machines for 3C industry (Computers, Communication and Consumer)

Force Control Commands

The feature supports two input methods:

  • Analog Command: +-10 VDC connected to CDHD2 analog input.
  • Digital Command: Serial (USB or RS232) or EtherCAT.

The Force Control Algorithm

  • Receive force setpoint in units of grams.
  • Limit the force set point by means of slope.
  • Read force sensor actual value via analog input and convert analog input from volts to Grams.
  • Force error = force setpoint – force sensor feedback
  • PI control loop

Typical Z axis Operational Sequence

  • Operation starts in Position mode.
  • Move axis to start position (above the pressed object).
  • Switch to Force Control mode.
  • Perform “Press” operation until force setpoint is reached.
  • Switches back to Position mode.
  • Moves back to start position.

Share This Post

Skip to content