Robotic Manipulation in Constrained Glovebox Environments

Technology

Re-Vector ZH® / Re-Vector ZH800 Robotic Arm

Application Area

Nuclear decommissioning and hazardous materials handling

The Challenge

Handling hazardous or radioactive materials tends to be carried out within sealed containment systems known as gloveboxes. Human operators perform these tasks by reaching in through integrated glove ports, finding this relatively easy as they possess the dexterity, adaptability and situational awareness needed to work effectively in highly constrained environments.

Replicating this capability with automation has to date proved extremely challenging. Traditional articulated robotic arms may be able to reach into the enclosure, but then have limited capability once inside. Entering through a single access point limits their movement options, leaving many areas difficult or impossible to reach and many tasks difficult to perform.

The reason humans cope so well is that the arm is not limited to bending at isolated hinge-like joints. It is capable of coordinated rolling and twisting movements distributed along its length. This type of motion enables a human operator to reach around obstacles, change posture and continue working where a conventional robot would effectively run out of options.

To arrive at a form of automation that improves productivity while minimising risk to human operators, one potential solution would be to emulate the capabilities of living creatures.

The Solution

Ross Innovation has developed a new type of robotic arm inspired by the characteristics of living creatures. Rather than relying on a handful of discrete single-axis joints, the Re-Vector architecture distributes steering capability throughout the arm. The result is a series of coordinated rolling movements that create fluid, organic motion, enabling the robot to coil, uncoil, reach around obstructions and continuously adapt its posture while maintaining precise control of its tool-head.

For a small-scale glovebox, the Re-Vector ZH800 robotic arm emulates the reach of an adult human’s arm. The larger Re-Vector ZH1700 is suited to tasks that require long reach, for example inside aircraft wings. An intermediate Re-Vector ZH1300 is suited to tasks that require reach longer than that of a human arm while being able to operate in confined spaces.

A digital twin of a representative glovebox environment has been developed to compare the robotic arm against its natural benchmark: the human operator. The study has demonstrated that the Re-Vector ZH800 can reach everywhere that a human arm can, via the glove ports, while also maintaining complete freedom to orient and manipulate its tool-head anywhere within that space.

The simulation examined three key capabilities:

• Workspace coverage from a single access point.
• Task-ready tool orientation throughout the enclosure.
• Null-space reconfiguration, allowing the arm to change posture while maintaining the same tool centre point.

As demonstrated, the arm can access shelves, floor-level work zones and recessed areas without requiring the base position to be changed. Once deployed, the tool-head can be oriented appropriately for manipulation tasks rather than simply achieving positional reach. Straight line movements, known as Cartesians, can be performed at any orientation, at any location within the glovebox.

In terms of situational awareness, the Re-Vector arms have force-torque sensing in all their joints plus data that can be obtained from depth cameras. These data streams, and others as required, can be used to create sensory feedback for a remote operator, or to semi-automate many routine operations.

Key Innovation

A significant characteristic of the Re-Vector architecture is its ability to adjust its posture without having to move the tool-head. In robotics this is termed null space exploration. For a human operator this is experienced as the ability to bend and twist the arm while maintaining a tool in a desired position. By reconfiguring internally, yet holding the tool centre point fixed, the arm can negotiate obstacles, alter stiffness characteristics and escape kinematic dead-ends without interrupting the task. Importantly, the planning space is uninterrupted: everywhere within the reach of the arm is exploitable. There are no zones that the robot’s planner is forced to reject.

In practical terms, this means the robot will be able to reach into and perform tasks to a human operator’s level and beyond. In terms of accuracy, repeatability and the ability to apply significant force while operating 24/7, this automation capability will far exceed that of a human operator.

Results

The glovebox case study has demonstrated that the Re-Vector ZH800 can:

• Operate from a single fixed access point.
• Reach all principal internal work zones.
• Maintain local Cartesian motion within confined spaces.
• Orient the tool-head into practical task-ready poses.
• Reconfigure its posture without losing task position.
• Continue operation in highly constrained environments where traditional articulated robots become limited.

The study provides a representative example of how distributed-steering robotic architectures could improve remote handling for nuclear decommissioning, hazardous material processing and other applications where human access is restricted or undesirable.

Looking Forward

For decades, glovebox operations have remained a fundamentally human task because the human arm is exceptionally well adapted to working in confined spaces and robots are not. The Re-Vector architecture demonstrates that a new generation of robotic manipulators can emulate those same characteristics, opening the way for safer, more productive and increasingly autonomous operation in hazardous environments.

While demonstrated in a simulated environment, the glovebox study emulates the types of constrained-space operations encountered in active nuclear facilities. The architectural principles expressed in a unique type of robot kinematics are also applicable to other sectors, including aerospace assembly, in-service inspection and maintenance and future autonomous operations in highly confined industrial environments.