This invention relates to an unmanned vehicle used for surveillance, inspection and/or detection purposes at a potentially unsafe site. BACKGROUND OF INVENTION

In certain isolated instances, radiation detectors are used to detect the presence of harmful radiation or ionizing radiation. A common source of ionizing radiation is radioactive materials that emit α, β, or γ radiation. Radiation detectors can generally detect different types of radiation and can be used to alert personnel of dangerous levels of radiation that could cause harm. Most radiation detectors are directional in nature. This means that radiation can only be detected in a specific direction, usually the direction in which the detector is pointed by an operator. Consequently, an operator or inspector could potentially fail to detect harmful scattered radiation waves which are not in line of sight of the detector. Multiple detectors may be required in certain environments to detect scatter caused by a radiation leak or spillage. However, multiple detectors make the system bulky and reduce its portability. In most cases the detectors are wired and cables are needed to relay measurements to a safe location where they can be interpreted. However, an operator must still move the detectors around to different locations which places him/her at risk.

The invention aims to address, at least to some extent, the drawbacks discussed above.

SUMMARY OF INVENTION

According to a first aspect of the invention, there is provided an unmanned vehicle which includes: a chassis;

drive means connected to the chassis, the drive means being configured to drive the vehicle forward and over obstacles by engaging a ground surface;

a power plant mounted to the chassis and drivingly connected to the drive means; and

an omnidirectional radiation detection apparatus connected to the chassis. In the context of this specification, "radiation" should be understood to refer to harmful radiation such as radiation emitted by radioactive materials. In other words, "radiation" can be understood to refer to ionizing radiation.

The radiation detection apparatus may include three radiation sensors which are configured to detect radiation in at least three, substantially orthogonal directions.

The radiation sensors may be substantially orthogonal relative to one another. The vehicle may include a telemetry module which is configured wirelessly to transmit measurements from the radiation detection apparatus to a remote monitoring station.

The vehicle may include a camera which is configured to stream video footage to the remote monitoring station. The video footage may be streamed wirelessly via the telemetry module. The camera may be mounted proximate to the radiation detection apparatus.

The unmanned vehicle may be a remote controlled vehicle. The drive means may include wheels. Alternatively, the drive means may include at least two continuous tracks. In the case of the drive means comprising wheels, the drive means may further include an at least partially exposed traction or drive belt which operatively runs along a bottom of the chassis. The drive belt may be configured to assist the vehicle to traverse obstacles. The drive means may include a pair of traction belts operatively running along a bottom of the chassis. One traction belt may be provided on each side. The belts may be parallel and run in a longitudinal direction.

The drive means may include belt-driven wheels. To this end the drive means may include a combination of wheels and at least two drive belts. The drive belts may be drivingly connected to the wheels. The drive means may include a pair of wheels connected to each side of the chassis. One drive belt may be connected to each pair of wheels. The power plant may include a pair of electric motors. One electric motor may be drivingly connected to a pair of belt-driven wheels. The power plant may include a battery. The wheels may be exposed.

To this end, the chassis may be a belt-driven wheeled chassis having a pair of wheels on either side of the chassis.

The vehicle may further include a platform which is mounted to the chassis. The platform may be vertically displaceable relative to the chassis. The platform may be a lifting platform. The radiation detection apparatus may be mounted to the platform. The vehicle may include an actuator which is configured to displace the lifting platform relative to the chassis between a collapsed position in which the platform is adjacent to the chassis and an extended position in which the platform is raised relative to the chassis. The lifting platform may include a scissor lift. The actuator may be connected between opposing legs of the scissor lift. The actuator may be configured to extend and retract the scissor lift and hence displace the platform between its extended and collapsed positions. The actuator may be a linear displacement actuator. The radiation detection apparatus may be displaceable relative to the chassis. The radiation detection apparatus may be linearly displaceable relative to the chassis. The radiation detection apparatus may be angularly displaceable relative to the chassis. To this end, the radiation detection apparatus may be linearly and angularly displaceable relative to the chassis. Accordingly, the radiation detection apparatus may be angularly displaceable relative to the platform. The radiation detection apparatus may be configured for omnidirectional radiation detection. Accordingly, the apparatus may be an omnidirectional radiation detector. In accordance with another aspect of the invention, there is provided a monitoring system which includes an unmanned vehicle as described above and a remote monitoring station which is in communication with the unmanned vehicle and is configured to communicate measurements received from the unmanned vehicle to an operator. The remote monitoring station may include a remote control through use of which an operator can control the unmanned vehicle. The remote control may be configured to control drive of the drive means and displacement of the platform relative to the chassis.

The remote monitoring station may be portable. In other words, the remote monitoring station may be a mobile monitoring station. The remote monitoring station may include a graphical display.

BRIEF DESCRIPTION OF DRAWINGS The invention will now be further described, by way of background, with reference to the accompanying drawings.

In the drawings:

Figure 1 shows a functional block diagram of a monitoring system in accordance with the invention which includes an unmanned or remote controlled vehicle in accordance with another aspect of the invention;

Figure 2 shows a three-dimensional view of the remote controlled vehicle with a lifting platform in an extended position;

Figure 3 shows a side view of the vehicle of figure 2;

Figure 4 shows a front view of the vehicle of figure 2;

Figure 5 shows another three-dimensional view of the remote controlled vehicle with the lifting platform in a collapsed position;

Figure 6 shows a three-dimensional view of a partially disassembled vehicle chassis; and

Figure 7 shows the vehicle of figure 5 climbing a set of stairs. DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT

The following description of the invention is provided as an enabling teaching of the invention. Those skilled in the relevant art will recognise that many changes can be made to the embodiments described, while still attaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances, and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not a limitation thereof.

In figure 1 , reference numeral 10 refers to a monitoring system in accordance with the invention which comprises a remote mobile monitoring station 12 which is manned by an operator and an unmanned vehicle 1 3, in the form of a remote controlled vehicle. The monitoring station 12 is in communication with the unmanned vehicle 13 and is configured to control the vehicle 1 3 by way of a remote control 14. The unmanned vehicle 13, in turn has a camera 16 mounted to it which wirelessly feeds back video footage of the vehicle's immediate surroundings to the monitoring station 12 so that the operator can manoeuvre the vehicle 1 3 around using the remote control 14. To this end, the monitoring station 12 includes a telemetry module 17, which is configured to receive wirelessly transmitted measurements from the vehicle 13, and a graphic display 18 which may be in the form of an LCD screen, which is configured to display the video feed received from the vehicle 1 3 to the operator. The unmanned vehicle, in this example embodiment, is in the form of a remote controlled vehicle 1 3. An omnidirectional radiation detection apparatus 20 is connected to a platform 22 of the vehicle 13 and is configured wirelessly to convey radiation measurements back to the monitoring station 12 via a telemetry module 23 provided on the vehicle 13. The radiation measurements may be displayed to the operator via the LCD screen 18 or via other suitable output devices such as lights, tactile output devices or buzzers etcetera (not illustrated).

The vehicle 13 includes a chassis 24, a power plant mounted to the chassis 24 and drive means connected to the chassis 24 which are collectively configured to drive the vehicle forward and over obstacles such as stairs. The power plant is drivingly connected to the drive means. In this example embodiment, the power plant comprises two rechargeable batteries 25 (see figures 1 and 6) which are connected to a pair of remotely controlled electric motors 26. Referring specifically to figure 6, the chassis 24 includes a square tube frame 41 , an outer periphery of which is closed off using sheet material 42 which is riveted to the frame 41 . The batteries 25 and electric motors 26 are arranged between longitudinally extending struts of the frame 41 within a cavity 43 defined by the frame 41 and sheet material 42. Each electric motor 26 is drivingly connected to a drive pulley 44. A drive belt 28 is arranged, in a fore-aft direction, around the drive pulley 44 and a number of idler rollers 46 which are rotatably mounted to the frame 41 . The drive belt 28 also passes around a pair of axle pulleys 47 which are in turn drivingly connected to a pair of wheels 30 rotatably mounted to the frame 41 for rotation about separate, longitudinally spaced apart rotation axes. Each pair of wheels 30, on either side of the chassis 24, is therefore driven by a separate drive belt 28. Two operatively lower, longitudinally spaced apart idler rollers 46 protrude partially through openings in the sheet material, toward opposing ends of the chassis 24, such that a length of each drive belt 28 is exposed and runs along a bottom of the chassis 24 in a fore-aft direction, over a base plate of the chassis 24. This configuration, which can best be seen in figures 3, 4 and 7, allows the vehicle 1 3 to climb stairs as shown in figure 7. In the position shown in figure 7, with the chassis 24 beached on an edge of a step, the drive belt 28 grips the edge of the step and serves to lift the chassis 24 over the edge helping the wheels to regain traction.

As mentioned above, the vehicle 1 3 includes a lifting platform 22 which includes a scissor lift 29 which is mounted to a top of the chassis 24. The camera 1 6 is mounted to a front edge of the platform 22. The vehicle 13 further includes a temperature sensor 31 , humidity sensor 32 and a remote control unit (RCU) 33 which is configured to receive command signals from the remote control 14.

The radiation detection apparatus 20 includes a body 34 which houses three orthogonal radiation sensors 35.1 , 35.2, 35.3 and suitable circuitry which are configured to detect radiation in at least three, substantially orthogonal directions. Accordingly, the sensors 35.1 , 35.2 are orientated in a horizontal plane and the sensor 35.3 is orientated in a vertical plane in a rear part of the body 34 which protrudes upwardly. The telemetry module 23 is configured wirelessly to transmit measurements from the radiation sensors 35 to the remote monitoring station 12. This obviates the need for personnel manually to monitor radiation levels using handheld devices. The system 10 therefore minimizes the risk of exposure of personnel to radioactive radiation. In this example embodiment, the sensors 35 are in the form of Geiger-Muller tubes configured in x, y and z axes to detect radiation omnidirectionally. In order further to improve its range of motion and omnidirectional sensing ability, the body 34 of the radiation detection apparatus 20 is rotatably mounted to the platform 22 for rotation about a vertical rotation axis. The apparatus 20 is therefore linearly or vertically and angularly displaceable relative to the chassis 24. Angular rotation of the apparatus 20 relative to the lifting platform 22 is affected by way of a servo-motor (not shown) remotely controlled. The apparatus 20 is configured to rotate 180 degrees relative to the platform 22.

The scissor lift 29 comprises a pair of opposing, two stage scissor-type frames 36 which are interconnected at corresponding positions by laterally extending stays 37 of equal length. To facilitate upward and downward movement of the scissor-type frames 36, upper and lower rearward ends of each frame are held captive in a linear guide 38, pin-in-slot fashion. A linear actuator 40, which is also remotely controlled via the remote control 14, extends obliquely between opposite sides of the scissor lift 29. Extension of the actuator 40 results in vertical extension of the lift 29 to its extended position shown in figures 2 to 4. Retraction of the actuator 40 causes the lift 29 to collapse to its collapsed position shown in figure 5. In order to steer the vehicle 13, the electric motors 26 driving the respective drive belts 28 are operated in opposite directions such that the wheels 30 on the left side of the vehicle turn in one direction and the wheels on the right side of the vehicle turn in an opposite direction forcing the vehicle 13 to turn in the appropriate direction. This form of steering can be referred to as skid steering. The lifting platform 22 is configured to displace 1 m vertically upward. The vehicle 1 3 is configured to clear obstacles to a maximum of 200mm vertically upward. The vehicle 13 weighs about 60kg and has an approximate width of 0.75m, height of 0.5m and length of 1 m.

It will be appreciated that other components or device may be mounted to the platform 22 as needed. In this instance, the vehicle 13 has been designed such that the platform can only be extended when the vehicle 1 3 is stationary to prevent accidental damage. The Applicant believes that the vehicle 13 is very cost effective when compared to other unmanned vehicles or inspection robots. Furthermore, through use of the monitoring system 1 0 including the vehicle 13, an operator will be able safely, easily and remotely to inspect a potentially radioactive site for radioactive radiation using the apparatus 20. Due to the fact that the vehicle 1 3 can climb stairs, manoeuvring of the vehicle 13 should not be a problem.