Robotic Manipulator Joint Braking for Safe Manual Extraction
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Solution Overview
Problem
Existing robotic manipulators lack adequate safety features to protect humans and deformable objects in close proximity, particularly during power loss or malfunction, and existing safety measures can cause harm or trap individuals.
Innovation Solution
Implementing a robotic system with removable or disabled brakes at key joints, solenoid-based detachment mechanisms, and user-controlled shutdowns to allow safe manual movement away from entities, combined with force sensors for immediate shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brakes are enabled at all joints to prevent uncontrolled movement during power loss, then safety is improved, but the ability to manually move the robotic arm away from entities is reduced
Solution Approach 1:
The brake system is segmented into two subsets: brakes at joints closer to the base (first subset) and brakes at joints closer to the end effector (second subset). During power loss, only the first subset remains enabled while the second subset is disabled, allowing selective application of braking force to different parts of the robotic arm.
Solution Approach 2:
Different braking characteristics are applied to different locations on the robotic arm. The base-proximal joints maintain full braking capability for stability, while the end-effector-proximal joints have reduced or no braking to enable manual manipulation and safe extraction from entities.
2Ease of operation
If brakes are disabled to allow manual movement, then ease of operation is improved, but safety during power loss deteriorates
Solution Approach 1:
The brake system is divided into two functional groups located at different positions on the robotic arm. The first group (base-proximal) provides safety through continued braking, while the second group (end-effector-proximal) provides operational flexibility through disabled braking, resolving the safety-maneuverability conflict.
Solution Approach 2:
The brake system dynamically adapts its characteristics based on location and operational state. During normal operation, all brakes are disabled for full maneuverability. During power loss, the system transitions to a mixed state where base-proximal brakes remain enabled for safety while end-effector-proximal brakes are disabled for safe extraction.
3Extent of automation
If standard shutdown procedures are used, then operational control is maintained, but the ability to quickly extract from entities during malfunction is reduced
Solution Approach 1:
The brake system is pre-configured with different operational states for different subsets of brakes. In the event of power loss or malfunction, the disabled second subset of brakes immediately allows manual extraction without requiring time-consuming procedural steps, while the enabled first subset maintains basic stability.
4Reliability
If force sensors are added for immediate shutdown detection, then safety response time is improved, but device complexity increases
Solution Approach 1:
The robotic arm leverages its own weight and the gravitational force acting on it as a detection mechanism. When power is lost, the unbalanced gravitational forces create observable movement or positioning changes that indicate a shutdown state, eliminating the need for additional force sensors while maintaining safety response capability.
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
Ensures safe disengagement of robotic manipulators from humans or objects, preventing injury and damage during power loss or malfunction, while allowing manual control for safe extraction.
Implementation Method 1
solenoid-based detachment mechanisms
Data Source
AI summary
An apparatus includes a base and a robotic arm operatively coupled to the base via a connector. The robotic arm includes a set of links interconnected by a set of joints. A first link from the set of links is operatively coupled to the connector. Each joint from the set of joints includes a brake from a set of brakes, each brake from the set of brakes configured to be enabled or disabled. The apparatus further comprises an end effector operatively coupled to the robotic arm via a second link from the set of links different from the first link. The apparatus further comprises a controller, communicably coupled to at least one of the base, the robotic arm, or the end effector. The controller is configured to cause the robotic arm to perform a task, and determine, during the task, that movement of the robotic arm is to be restricted.