Integrated Robot Joint Drive Module With Output-Side Encoder Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing robot drive modules lack high precision and compactness, particularly in collaborative and humanoid robots, due to limitations in mechanical precision, encoder accuracy, and sensitivity to radial errors and gear backlash, which affects their ability to perform high-precision tasks and maintain safety in applications like metrology and medical surgery.
Innovation Solution
A compact robot drive module design featuring a rotary drive with a motor circuit board, stator, and rotor, integrated with a gearbox and a rotary encoder on the input side, connected via a rigid part to the gearbox output, allowing for precise rotation feedback and control, and optionally including dual rotary drives and absolute angle measurement using hall sensors and magnets, to enhance precision and reduce bulkiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotary encoder is mounted on the gearbox output axis as an independent module, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent integrates the rotary encoder directly into the gearbox structure, merging two previously separate components (encoder and gearbox) into a unified assembly. The encoder is mounted on the gearbox housing with its measurement axis aligned to the output shaft, eliminating the need for separate encoder mounting brackets and cabling while maintaining measurement precision.
Solution Approach 2:
The gearbox housing serves multiple functions: it encloses the gear mechanism, provides structural support, and acts as the mounting base for the rotary encoder. This multi-functional design reduces the number of separate components needed and simplifies the overall device structure.
2Reliability
If the encoder is placed after the gear box in a motor/gear-setup, then sensitivity to radial error and gear backlash is reduced, but additional cabling and space are required
Solution Approach 1:
The encoder is integrated directly onto the gearbox housing, combining the feedback mechanism with the transmission system. This eliminates the need for separate encoder mounting structures and reduces cabling requirements while maintaining the encoder's position after the gearbox to avoid radial errors and backlash.
Solution Approach 2:
The gearbox housing acts as an intermediary structure that provides a stable mounting base for the encoder. By mounting the encoder on the housing rather than directly on moving components, the design achieves both measurement reliability and installation simplicity.
3Area of stationary object
If the angle encoder measures the angle with the shafting structure in the joint, then installation space is reduced, but sensitivity to radial error of the joint shafting structure increases
Solution Approach 1:
The encoder measures the angular position of the gearbox housing rather than directly coupling to the output shaft. The housing serves as an intermediary that provides a stable reference frame, isolating the measurement from radial errors in the shafting structure while maintaining compact installation.
Solution Approach 2:
The measurement function is separated from the power transmission function. The encoder measures the housing position independently from the shaft rotation, allowing the measurement system to be insensitive to mechanical errors in the transmission path while maintaining compact integration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides high-precision position feedback and control, reduces the need for additional cabling, and ensures coaxial accuracy, enabling robots to perform complex tasks with improved safety and efficiency in compact configurations.
Implementation Method 1
a rotating part of the angle encoder rotates coaxially along with the measured axis, and determines the rotation angle and position relative to a fixed part of the angle encoder... The first unit is wholly or partly scanned by means of a scanning signal from a scanning unit attached at the second unit
Implementation Method 2
a rotary drive comprising a motor circuit board, a stator, and a rotor, wherein the rotor is configured to rotate—controlled by the motor circuit board—relative to the stator about an axis of rotation
Implementation Method 3
a gearbox configured to transform—according to a defined gear ratio—a rotary motion of the rotor about the axis of rotation into a rotary motion of a gearbox output component about the axis of rotation
Implementation Method 4
absolute angle measurement using hall sensors and magnets
Data Source
AI summary
A robot drive module for driving a rotary joint movement of a robot with at least a rotary drive and at least a rotary encoder arrangement and a method for a robot having such a robot drive module.