Robot Joint Assembly With Rotor Brake for Safe Torque Control
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Solution Overview
Problem
Existing robotic joint assemblies face challenges in minimizing dynamic forces, which can lead to hazardous situations when robots interact with humans, particularly due to increased torque and precision issues when handling loads close to the arm's fixation point, and there is a need for a compact and reliable design that reduces the risk of accidents.
Innovation Solution
A joint assembly featuring a strain wave gearing system with a wave generator, flexspline, and circular spline, integrated with a rotor brake and sensors to measure position, along with a planetary gear for reduced inertia, and a brake system to prevent free rotation in case of flexspline failure, ensuring safety and precision by minimizing dynamic forces and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the robot is configured to carry a load close to the fixation point of the arm, then the torque and dynamic forces are reduced, but the precision and control reliability must be maintained to prevent hazardous situations
Solution Approach 1:
The brake system is pre-configured to engage automatically upon detection of flexspline failure or loss of drive control, preventing uncontrolled movement before hazardous situations can occur. Sensors continuously monitor the drive system state and trigger the brake in advance of potential accidents.
Solution Approach 2:
The brake system acts as an intermediary safety mechanism between the drive system and the load. It provides a controlled stopping action that prevents direct uncontrolled movement of the load, mediating the transition from normal operation to safe stopped state.
2Force
If the joint assembly is made compact to minimize dynamic forces, then the inertia is reduced, but the space for safety components like brakes and sensors is limited
Solution Approach 1:
The brake system is merged with the existing joint assembly structure, utilizing the housing and mounting points already present in the compact design. Sensors are integrated into the drive system components, eliminating the need for separate dedicated sensor housings and reducing overall complexity.
Solution Approach 2:
The brake components are nested within the existing joint assembly housing, utilizing available internal spaces. Sensors are positioned within the drive system components themselves, creating a nested arrangement that maximizes space utilization in the compact design.
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 a compact, reliable, and safe joint assembly that reduces dynamic forces and torque, enhancing precision and safety by preventing hazardous situations, allowing robots to interact closer to humans without risking accidents.
Implementation Method 1
a rotor brake configured to stop/prevent relative movement between the rotor shaft and the flexspline
Implementation Method 2
a strain wave gearing system comprising: a wave generator, a flexspline, and a circular spline connected to the output part, wherein the wave generator is rotated by a rotor shaft
Data Source
AI summary
The present invention relates to a joint assembly (1) for a robot (100), comprising a housing (26) connected with an output part (8), the housing comprising a housing wall (26A), a strain wave gearing system (90) comprising a wave generator (7), a flexspline (13), and a circular spline (36) connected to the output part (8), wherein the wave generator (7) is rotated by a rotor shaft (3), the rotor shaft being driven by an electric motor (140) comprising a stator (15) and a rotor magnet (16), the rotor magnet (16) being affixed to the rotor shaft (3), and wherein the joint assembly (1) further comprises a rotor brake (30) configured to stop/prevent relative movement between the rotor shaft (3) and the flexspline (13), and sensors arranged to measure the position of the housing (26) in relation to the output part (8). Furthermore, the present invention also relates to a robotic arm (100) comprising a joint assembly according to the present invention and to the use of the joint assembly according to the present invention.