Exoskeleton Control via Ground Force and Tilt Sensors
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Solution Overview
Problem
Existing locomotion assisting exoskeleton devices lack intuitive and natural control methods, particularly for paraplegic users, and do not provide adequate feedback for safe operation, limiting user control and safety.
Innovation Solution
An exoskeleton bracing system with ground force sensors and a controller that identifies user stances to actuate motorized joints for locomotion modes, including alerting devices for hazardous situations, allowing users to control the device through shifts in body weight and tilt sensors for safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control is achieved through upper body tilt sensing, then gait initiation and maintenance can be triggered, but user control is limited and cannot indicate which leg to initiate gait with
Solution Approach 1:
The control system is segmented into multiple independent sensing channels: upper body tilt sensors for gait initiation, and foot/leg sensors for selecting which leg to move. This segmentation allows each sensor type to handle specific control aspects, resolving the limitation where tilt-only control could not specify leg selection.
Solution Approach 2:
The patent introduces intermediary sensors (foot pressure sensors, leg position sensors) that mediate between the user's intent and the device's action. These intermediaries provide additional control dimensions, enabling the user to specify both gait initiation and leg selection separately.
2Extent of automation
If the device operates automatically based on tilt detection, then gait sequence can be maintained, but safety feedback and hazard detection are insufficient
Solution Approach 1:
The patent implements multiple feedback loops: sensors continuously monitor foot position, leg orientation, and upper body tilt, providing real-time feedback to the controller. This feedback enables the system to detect hazardous situations (such as improper foot placement) and alert the user, while maintaining automatic gait execution.
Solution Approach 2:
The system uses sensors to detect potential hazards before they become dangerous situations. For example, foot pressure sensors detect improper foot placement early in the gait cycle, allowing the system to alert the user before a fall or injury could occur.
3Ease of operation
If nerve signal detection is used for control, then intuitive movement intention can be detected, but it cannot be used by paraplegic users whose nerves do not transmit signals
Solution Approach 1:
The control system is designed to be universal by supporting multiple control modes: nerve signal detection for users with intact nerve transmission, and alternative sensor-based control (tilt sensors, foot pressure sensors) for paraplegic users. This multi-functionality ensures the device can serve diverse user populations with different physiological capabilities.
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
Enables effective, intuitive, and safe control of locomotion assisting exoskeleton devices by paraplegic users, providing real-time feedback and enhancing safety through ground force and tilt sensor integration.
Implementation Method 1
one or more ground force sensors designed to sense ground force exerted on each of the leg braces
Implementation Method 2
tilt sensors for safe operation
Data Source
AI summary
An exoskeleton bracing system includes: a trunk support for affixing to the trunk of a disabled person and leg braces for connecting to the legs of the person, each leg brace including limb segment braces. Motorized joints are adapted to provide relative angular movement between the limb segment braces of the leg braces and between the leg braces and the trunk support. One or more ground force sensors are designed to sense ground force exerted on each of the leg braces. The system also includes a controller for receiving sensed signals from said one or more ground force sensors, with an algorithm for identifying a stance from the sensed signals and, based on the identified stance, actuating the motorized joints to perform an action relating to a mode of locomotion selected from a set of predefined actions corresponding to the identified stance.