ABP’s Guardian set to enter service

A highly versatile remote- controlled bomb disposal robot with inbuilt spatial awareness is due to enter service with a NATO country later this year.

The Guardian miniature remotely operated vehicle (MROV) has been developed by Poole-based AB Precision (ABP), which employs less than 100 people but competes with some of the biggest names in global security technology.

ABP claims the device (pictured below left) has far greater capability than other small robots in its class. It can reach overhead and down into drains and, in a key development, knows its own position in relation to its suroundings. It could also be used for nuclear decommissioning, moving sensing equipment into hazardous areas and manipulating dangerous objects.

The Guardian can be fitted with various tools and payloads suitable for different tasks, powered and controlled through on-board supplies and serial communication ports. The equipment includes a high-pressure water jet, which can render an explosive device ineffective, a real-time X-ray system, a chemical agent monitor and an explosives sniffer.

The MROV travels on four independently driven tank-style track modules, which give it four-wheel drive capability.

The tracks can be turned through 360º in independent pairs, so can be made very stable when the maximum footprint is used, or reconfigured to a smaller footprint, allowing access to confined spaces. Tractor tread wheels can also be fitted to the tracks to further improve off-road mobility.

By turning the tracks on end so the robot stands on ‘tip-toes’ with its its multi-jointed arm fully extended, the Guardian has the ability to reach up to 2.6m to investigate or deploy equipment at height. This allows it to carry out traditionally difficult tasks such as operations in overhead lockers of aircraft or in high shelves and cupboards.

The arm can also be used along or below the ground to work under cars or in manholes and drains. ABP claims this level of versatility is unique compared with other ROVs in its class.

The robot is controlled remotely from a briefcase-sized console, which displays a view from the four on-board cameras (pictured above right) to give the operator situational awareness.

There are dedicated joystick controls for common functions, including movement and limb control, and a touch-screen menu-based interface for control of other vehicle functions and configurations.

Sensor feedback provides active traction control at all times. When the joystick is not activated, the brakes automatically engage to prevent the robot moving.

Nigel Peter, ABP project engineer, said: ‘The vehicle is operated by a bi-directional COFDM [a method of encoding digital information] radio link or bi-directional fibre optic link. The uplink from base station to vehicle sends command control and audio data, and the back-link contains video, audio, and sensor information.’

In addition to the operator’s instructions, Guardian has a degree of autonomy provided by 10 on-board magnetic rotary encoders supplied by motion-control technology developer Renishaw.

These AM512 sensors use the Hall effect — where moving a conductor through a magnetic field produces a voltage — to detect the positions of all the articulated components, such as the arm and track, and feed back the telemetry to the base station.

Individual microprocessors in the MROV read the data from the sensors and send it to the robot CPU.

This data is then relayed over the telemetry link to the base station, where it is displayed as a 3D image of the robot on a computer screen and used to provide automated configuration and collision avoidance. ABP has also developed proprietary software that halts further movement if two parts are about to collide. This gives the robot advanced electro-mechanical spatial awareness.

Kevin Cross, ABP general manager, said: ‘We chose the Renishaw sensors as they are a physically compact and easily implemented method by which we have been able to gather seamless and absolute 360º positional data collection from all mechanical moving parts of Guardian.’

The Guardian also has several configuration options that will automatically place vehicle elements into the optimum position for common tasks such as stair climbing.

Peter said the main technical challenge in developing the robot was careful packaging of all the required features internally to ensure that the vehicle was fully versatile to the end user.

Development began in 2003 and the pre-production model was introduced in 2007. Various improvements were made and the production was launched in the middle of last year, with the first unit going into service this year.

Cindy Barfoot, ABP project manager, said ABP consulted with users before designing Guardian, successor to its Cyclops robot, which has been in service for 15 years.

There are plans to design future models to allow different physical attachments to be fitted to the main body, for scenarios other than investigative and disarming duties.

The future for the Guardian and MROVs in its class appears to be robust, as more defence and homeland security systems are introduced to lessen casualties encountered in theatre and at disaster scenes.

The US Congress has passed legislation stipulating that by 2015, one-third of the army’s operational ground combat vehicles should be unmanned and similar initiatives are under way with the US Navy and marine corps.

A study by Wintergreen Research last year claimed MROV markets worth $441m (£294bn) in 2007 will reach $43.7bn by 2014, with growth expected to come from countries, law enforcement agencies, fire departments, and first responders implementing automated processes.

Berenice Baker