Modular Reconfigurable Robots in Space Applications

Robots are automatic electro-mechanical devices resembling humans or animals that are controlled by an electronic circuitry or computer program. There are different types of robots that are used for different types of applications. Recent trends in robotic technology have been developing advanced robots such as surgical robots are remote manipulators that are used for surgeries (especially keyhole surgery), walking robots that are mostly multi legged that are capable to move by walking, microbots and nanobots are microscopic and these nano robots or nano devices that are used in the human body to cure diseases, the rovers are robots with wheels that are used to walk on other planets for space exploration. Typically, robots used in space applications are autonomous robots, modular reconfigurable robots or self-reconfigurable modular robots, and so on.

Modular Reconfigurable Robots

Modular reconfigurable robots are generally autonomous kinematic devices with adjustable morphology. In fixed-morphology robots only the conventional tasks such as actuation, sensing and controlling are only able to perform. But, self-reconfigurable robots or modular reconfigurable robots are capable to change their own shapes by reorganizing their parts connectivity such that for adapting new circumstances, performing new tasks, and to recover from damages.

These self-reconfigurable robots can be defined as robots that can change their shape based on the path they have to pass through. For example, if a robot has to pass through a narrow pipe, then it will reconfigure itself in the shape of a worm and if it has to cross an uneven terrain, then it will reconfigure its shape with spider like legs. If there is a flat terrain, then it will reconfigure itself as a ball like structure for quick movement.

These reconfigurable robots are again classified into two types based on design. Such as homogeneous modular robotic systems consists of several modules with similar design to form a structure such that to perform a required task. A heterogeneous modular robotic system consists of several modules with different designs each of which performs specific functions and these are used to form a structure that performs a required task.

Reconfigurable Robots in Space Applications

As a part of research over the other planets, many countries are frequently launching several satellites or space missions to study the conditions and characteristics of the planets. Thus, for obtaining long term data, long term space missions are being launched and these long term space missions are typically self-reconfigurable systems.

These self-reconfigurable robots are capable of handling unforeseen situations and self-repair in case of any damages. We know that space missions are huge and mass constrained, so it is beneficiary if we use self-configurable robots that can perform multiple tasks instead of multiple robots that each perform only one particular task.

Till date, humans have set foot other than planet earth is only the moon. Whereas, modular robots used in space applications are being launched on many other planets. A series of landers, manipulators, orbiters, and rovers sent to Mars are famous robots used in space applications.

Robotic Manipulators and Rovers

There are various types of tasks that are performed by articulated robots in space. The process of servicing the apparatus or equipment in space is called as space manipulation which is done by articulated robots. Polybot suits well for space station or satellite maintenance and inspection. Robotic manipulators are projected for positioning in space or on other planets for emulating human manipulation abilities. They are generally positioned on free-flyer spacecraft or on orbit tuning of other spacecraft, within space vehicles, planetary landers, and rovers for acquiring samples.

Robotic rovers are projected for positioning on planets for emulating human movement abilities. They are frequently positioned on the terrestrial planets surfaces, small solar systems, aerobots (planetary atmospheres), cydrobots (ice layers), and hydrobots (liquid layers).

Automated Design and Optimization

Modular reconfigurable robots or modular robotic system is combined with software tools for assisting to select and design the finest morphology and control structure for performing each particular task. Although many traits of this design will unavoidably depend on human intelligence for the predictable future, other traits are acquiescent for automated design and optimization. All reconfigurable robots used in space applications must be designed such that capable to survive with launch stresses, radiation in the space, the vacuum, planetary distribution, and environment of the planet (planet on which reconfigurable robots are used or on target planets).

There are two types of designs of reconfigurable robots and they are: Lattice based designs and Chain based designs.

In lattice based designs, reconfiguration is easy, but it is hard to generate motion and this design requires more number of connectors and actuators.

In chain based designs, reconfiguration is hard and has insufficient stiffness, but it is easy to generate motion.

Modular Reconfigurable Robot Simulation

A software simulation environment based on physics, was developed using C++ that facilitates users for constructing reconfigurable robots utilizing a various types of modules. Additional module types are added with compatible connectors for extending the simulation.

Practical Example of Self-Reconfigurable Modular Robot

Modular transformer is one of the frequently used reconfigurable robots and these M-TRAN modules are used to form 3-D structure (that can change its own configuration and also capable to generate small robots), multi-DOF robot (that flexibly locomotes), and metamorphosing robot. This modular transformer consists of two actuators and battery.

Internal block diagram of the M-TRAN module, it consists of Li-ion battery, non-linear spring, power supply circuit, main CPU, acceleration sensor, permanent magnet, SMA coil, connecting plate, and PIC.

These reconfigurable robots are used in space applications for achieving the specific goals such as telecommunication provision, observation over earth for data return, military feasibility, and navigation purposes.

There are many other robotic based projects and applications:

• Ultrasonic Obstacle Sensed Robotic Vehicle
• Robotic Vehicle Movement by Cell Phone
• Robotic Vehicle Operated by a TV Remote
• Track Sensing Robotic Vehicle Movement
• Fire Fighting Robot
• Voice Controlled Robotic Vehicle
• Pick N Place Robot Controlled by Android Wirelessly
• Metal Detector Robotic Vehicle
• Auto Metro Train to Shuttle between Stations
• RF Controlled Robotic Vehicle
• Touch Screen Based Remote Controlled Robotic Vehicle

Hope this article gives brief information about modular reconfigurable robots used in space applications. For more information regarding robotic based electronics projects you can approach us by posting your queries in the comments section below.

Photo Credits

• Robots Used in Space Applications by robotnor
• Lattice Based Designs of Male Reconfigurable Robot by csail.mit
• Chain Based Designs of Reconfigurable Robot by wikimedia
• Internal Diagram of M-TRAN Module by slidesharecdn