Dual-Drive Controller Structure for Rigid, Accurate Machine Axes
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Solution Overview
Problem
Machine axes with speed-changing devices have low rigidity, resulting in reduced dynamics and positioning accuracy due to the inherent low rigidity of these devices.
Innovation Solution
A controller structure that determines a speed setpoint value based on position setpoint and actual values, with a second speed controller adjusting the second drive's force setpoint value, and additional pre-control values to enhance dynamics, including high-pass and low-pass filtering to optimize the load distribution between the first and second drives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a speed-changing device is used in the machine axis, then the machine can achieve speed variation and mechanical advantage, but the rigidity of the machine axis decreases resulting in lower dynamics and positioning accuracy
Solution Approach 1:
The machine axis is divided into two independent drive systems: a first drive acting directly on the machine element for high-rigidity positioning, and a second drive acting via the speed-changing device for speed variation. This segmentation allows each drive to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent combines two drive systems (first drive and second drive) with different characteristics into a single machine axis. The first drive provides high rigidity through direct connection, while the second drive provides speed variation through the speed-changing device, merging their advantages to overcome the traditional trade-off.
2Power
If a speed-changing device is used in the machine axis, then the machine can achieve mechanical advantage, but the rigidity of the machine axis decreases resulting in lower dynamics
Solution Approach 1:
The drive system is segmented into two parallel paths: one through the speed-changing device for mechanical advantage and power transmission, and another direct path for high-speed dynamic response. This allows the system to achieve both mechanical advantage and high dynamics simultaneously.
Solution Approach 2:
The control system dynamically switches between and combines the outputs of the first drive (direct action) and second drive (via speed-changing device) based on the required operating conditions, enabling the system to adapt between high-power and high-dynamics modes as needed.
Data Source
AI summary
A first drive operates directly on a machine element, whereas a second drive operates on a machine element via a speed-changing device. A position controller receives a position setpoint value and a position actual value of the machine element and determines therefrom a speed setpoint value for the machine element. A first determining device receives the speed setpoint value and determines a resulting speed setpoint value using the speed setpoint value. A first speed controller determines a first force setpoint value from the resulting speed setpoint value and the speed actual value of the machine element and controls the first drive depending on the first force setpoint value. A second speed controller determines a second force setpoint value from the resulting speed setpoint value and the speed actual value of the second drive and controls the second drive depending on the force setpoint value.