Control of a glove-based grasp assist device
Inventors
Bergelin, Bryan J • Ihrke, Chris A. • Davis, Donald R. • Linn, Douglas Martin • Sanders, Adam M • Askew, R. Scott • Laske, Evan • Ensley, Kody
Assignees
GM Global Technology Operations LLC • National Aeronautics and Space Administration NASA
Publication Number
US-9120220-B2
Publication Date
2015-09-01
Expiration Date
2032-02-29
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Abstract
A grasp assist system includes a glove and sleeve. The glove includes a digit, i.e., a finger or thumb, and a force sensor. The sensor measures a grasping force applied to an object by an operator wearing the glove. The glove contains a tendon connected at a first end to the digit. The sleeve has an actuator assembly connected to a second end of the tendon and a controller in communication with the sensor. The controller includes a configuration module having selectable operating modes and a processor that calculates a tensile force to apply to the tendon for each of the selectable operating modes to assist the grasping force in a manner that differs for each of the operating modes. A method includes measuring the grasping force, selecting the mode, calculating the tensile force, and applying the tensile force to the tendon using the actuator assembly.
Core Innovation
The invention disclosed is a grasp assist system comprising a glove and a sleeve, where the glove includes a digit, a force sensor measuring a grasping force applied by an operator, and a tendon connected to the digit. The sleeve contains an actuator assembly connected to the other end of the tendon and a controller. This controller includes a configuration module with selectable operating modes and a processor that calculates a tensile force to apply to the tendon differently according to each operating mode. This construction allows assistance in grasping by applying a calculated tensile force to the tendon via the actuator assembly, based on the measured grasping force and selected operating mode.
The problem addressed by the invention arises from repetitive or sustained grasping tasks that can stress an operator’s hands, fingers, and forearms, causing a decline in grip strength and productivity over time. Grip strength also varies among operators due to differences such as physical stature, injuries, or muscle fatigue, which can result in inefficient execution of grasp-related tasks. Existing ergonomic workplace designs cannot fully alleviate the stress induced by such manual operations, necessitating a device that can assist the operator’s grasp in a configurable manner to improve efficiency and reduce fatigue.
The summary further describes the system as including multiple flexible tendons selectively tensioned by actuators, with force sensors providing feedback signals to a controller that computes required tensile forces for different operating modes. The method involves measuring the grasping force, selecting an operating mode including force-based and position-based modes, calculating a corresponding tensile force, and applying it via actuators to assist the operator’s grasp. The device is wearable on the hand and forearm and integrates sensors, actuators, and control logic to tailor assistance to the operator’s needs and the task.
Claims Coverage
The patent includes several independent claims focusing on systems and methods for controlling a glove-based grasp assist device with multiple inventive features.
Grasp assist system with configurable operating modes
A grasp assist system comprising a glove with a digit, a force sensor measuring grasping force, and a tendon connected to the digit, combined with a sleeve containing an actuator assembly connected to the tendon and a controller. The controller includes a user interface, a configuration module with multiple selectable operating modes including force-based and position-based modes, and a processor configured to calculate and apply tensile forces to the tendon according to the selected mode.
Grasp assist system with multiple digits and actuators
A system with a glove having five digits and a force sensor positioned at the thumb to measure grasping force, four tendons connected to the four fingers, a sleeve containing a controller in communication with the sensor, a user interface displaying selectable operating modes, and four actuator assemblies each connected to a tendon. The controller calculates tensile forces to apply to the tendons for each selectable operating mode and controls the actuators accordingly.
Method for controlling a grasp assist system with selectable modes
A method including measuring grasping force via a force sensor on the glove, selecting from user-selectable operating modes including at least one force-based and one position-based mode, calculating a tensile force to apply to a tendon routed through a finger, and applying the tensile force via an actuator assembly to assist the operator in grasping.
The claims protect systems and methods employing a glove and sleeve with sensors, tendons, actuators, and a controller configured with selectable operating modes that calculate and apply tensile forces to assist grasping. The inventions cover both the hardware components and control methods adaptable to different grasp assist modes.
Stated Advantages
Assists operators in grasping objects by augmenting their grip strength, reducing fatigue during repetitive or sustained grasping tasks.
Provides selectable operating modes including force-based and position-based controls, enabling adaptable assistance tailored to different tasks or operator needs.
Includes biometric monitoring capabilities to customize operation based on biometric information such as muscle activity or fatigue signals.
Enables tracking and monitoring of operator performance and grasp strength over time, supporting rehabilitation and productivity management.
Documented Applications
Assisting human operators in manual work tasks requiring grasping to reduce fatigue and improve performance during repetitive or sustained grip activities.
Use in rehabilitation scenarios to augment grasp strength of operators recovering from injury, including monitoring and tracking grasp strength progress.
Monitoring operator health and fatigue via biometric sensors for worker management in industrial environments.
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