Hand research

The Shadow Hand

• provides 24 movements, allowing a direct mapping from a human to the robot.
• is capable of holding its own weight of about 3.9Kg.
• has integrated sensing and position control, allowing precise control from off-board computers, or integration into your existing robot platform.
• contains an integrated bank of 40 Air Muscles which make it move. The muscles are compliant, which allows the Hand to be used on soft or fragile objects, and importantly make the Hand safe around human beings.
• can be fitted with touch sensing on the fingertips, offering sensitivity sufficient to detect a single small coin.
• has a Controller Area Network (CAN) bus interface to the outside world.
• is available in right and left hand versions.
• http://www.shadowrobot.com/hand/techspec.shtml
• in Summer 2008 a version was designed with electric actuators instead of the pneumatic muscles.

"Our Utah/MIT hand does not incorporate tactile sensing."

Note the cumbersome control apparatus required for the hand.

A three-fingered, nine degree of freedom (DOF) Stanford/JPL hand equipped with Brock fingertip load cells for tactile sensing, mounted on a five DOF GE P50 robot arm.

elumotion - Elumotion Hand

The Sheffield Hand is an articulated model of the human upper-limb. It was researched and developed at Sheffield Hallam University.

The aim of the project was to elicit knowledge on appropriate mechanical articulations that would permit life-like movement of a replica of the human arm. In addition to adding to knowledge, this project resulted in several tangible models. During this research, several international universities were contacted working on ‘artificial muscle’ materials.

It was considered appropriate to provide some of the Sheffield models to these laboratories in order to advance the state of the art in upper-limb prosthetics. One of the arms also went to the NASA Jet Propulsion Laboratories where it is being used as a test rig for their ongoing research into artificial muscle materials.

Dexterous Manipulation
Robotic grasping
This work deals with teaching by demonstration and learning of grasp primitives for dexterous robotic hands.
Elumotion Ltd. Actuated Sheffield Hand

Elumotion Ltd. manufactured a replica of the Sheffield Hand for Orebro University and subsequently devised an actuation strategy for 12 degrees of freedom of this hand.

Following from the findings of the development of the Sheffield Hand, the actuation components were designed in modules. Each module to power the flexion and extension of the finger comprises telescopic rods, complete with a series elastic element.

The rods pull on ‘tendons’ to the fingers, in a similar manner to how the real hand works. A second smaller module, based on a similar principle’, moves the fingers from side to side and is situated in the space of the hand. Work on this hand is ongoing.

13Feb07 - http://www.touchbionics.com/professionals.php?pageid=37§ion=2

The high definition silicone rubber skin offers a similar aesthetic appearance to current high definition passive covers.

3. Using a traditional myoelectric two-signal input, the i-LIMB Hand’s 5 powered motors operate using Touch Bionics’ unique controls system. Existing myoelectric users quickly adapt to using the new device and can quickly start to utilise the device’s new functionality. For new patients, the i-LIMB Hand offers a prosthetic solution that has never been available before –Touch Bionics’ goal has been to truly transform the life options for patients.

4. The modular nature of design and the individually powered and self contained digits of the i-LIMB Hand offer the clinician the chance to configure hand prostheses in a more versatile manner than previously possible. True partial hand prostheses are now possible for the first time with this design.

Grip Patterns
Existing first generation hand prostheses all consist of a major compromise – only one grip posture is available to users. This clearly limits and reduces the functionality of the prehensive function of the prosthesis. The i-LIMB™ Hand offers a step change in grip functionality by offering the user the choice to configure the hand into proven dextrous grips. By a simple rotation of the thumb the user can select power, tip or key grip to give the i-LIMB Hand better gripping postures for tasks of daily living.

Click on this link to view a five minute documentary from the UK's Channel 4 showing the i-LIMB Hand in action. Visit the 'Video of i-LIMB Hand in Action' page to see more clips.

The i-LIMB Hand is available in a compatible version to a widely used wrist, electrode and battery system. This allows existing users to have the advantages of the i-LIMB Hand without the extra cost of purchasing new power and control hardware and also without changing sockets.

The Touch Bionics i-LIMB Hand has been developed with the three most common choices of gripping configurations used by humans: the power grasp of articulating digits, (for example to hold a mug of tea), the precision grasp of thumb against first and second finger (for example to pick up a pen) and the key grip of thumb against proximal phalanx of the index finger (for example to turn a key).

It is envisaged that the thumb can be passively adjusted into the correct position to allow these three grips to be realised. This is possible largely due to the independent nature of the ProDigits™ technology, which means that there is no physical and constraining linkage between digits and thumb.

The Touch Bionics i-LIMB Hand achieves its grip strength of around 45N (10lbsf) from the vector sum of its articulated fingers powered by ProDigits™ units. In its strongest manifestation there are three powered fingers and a powered thumb (the little finger is slaved to the third finger).

Adaptive Grip
This grip means that the thumb can rotate through a number of different positions so that it can achieve a variety of grip patterns.

Compliant Grip
This grip means that each of the motors within the digits is allowed to stall individually. This enables patients to grip a convex or concave object. In contrast, traditional prosthetic hands are only able to grip objects with parallel sides.

Anthropologically appropriate
This is a major break-through: the Touch Bionics i-LIMB Hand is the first prosthetic hand to imitate the shape and form of a human hand.

The Edinburgh Electric Hand originated from the clinical and prosthetic design experience of David Gow of Touch EMAS Ltd.

The concept proposed was an electric hand possessing multi-articulated digits and a powered thumb that could be positioned laterally and into opposition with the fingers. Crucially, the mechanisms within the hand needed to fit within a silicone glove that was modeled from a real hand.

Elumotion Ltd. used a technique of sectioning a resin replica of a real hand to generate a computer model into which the virtual components of the hand were fitted. A working prototype was then manufactured ‘in-house’ which can be seen being tested for grip strength within its silicone glove.

ATR and Honda Successfully Develop New Brain-Machine Interface Creating Technology for Manipulating Robots Using Human Brain Activity.

Although the hand is shown just adopting the position of the hand of the human controller it seems to have sensors over the palm and fingers indicating use as a real robot hand.

In collaboration with the Developmental Cognitive Machines Lab. at the University of Tokyo (Prof. Hiroshi Yokoi), we have developed a prosthetic robotic hand inspired by the muscle tendon system of the human hand. The robotic hand has 13 degrees of freedom, and each finger has been equipped with different types of sensors (i.e., flex/bend, angle, and pressure).

At the Biomechatronics lab, medical system engineering department, at Chiba university (Prof. Wenwei Yu) in Japan, the same robotic hand has been used as a prosthetic device. EMG signals can be used to interface the robot hand non-invasively to a patient and electrical stimulation can be used as a substitute for tactile feedback.

The Orthopaedic University Hospital Heidelberg' Fluidhand can close round irregular objects. Located within the movable finger joints are flexible drives operating on the same principle as spider's legs. Elastic chambers are pumped up by miniature hydraulic systems, allowing fingers and thumb to be moved independentley.
The Engineer 5-18 May 2008

RAPHaEL (Robotic Air Powered Hand with Elastic Ligaments) developed at The Robotics and Mechanisms Laboratory (RoMeLa) of the College of Engineering at Virginia Tech.
Powered by a compressor air tank at 60 psi and a novel accordion type tube actuator.