Space Robot: Design, Applications, and Testing - Engineering Report

This report provides a comprehensive overview of space robot design, implementation, and applications. It begins with an introduction to robots and their increasing role in space exploration, followed by a detailed examination of the control system design methodology, including hierarchy of desired behavior, levels of autonomy, and remote/local partitioning. The report then categorizes space robot applications into operations, maintenance, in-orbit positioning/assembly, and resupply, providing specific examples such as scientific experimentation and space servicing functions. Challenges in designing and testing space robots are discussed, focusing on the effects of zero-g environments, vacuum, and thermal conditions, along with other factors like material selection and radiation protection. System verification, testing, and performance assessment, including calibration methods, are also covered. The report concludes with insights into ongoing developments and the importance of reliability in space robotics.

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SPACE ROBOT
By Name
Course
Instructor
Institution
Location
Date

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INTRODUCTION
A robot is a man-made object which is using the computer as its brain and has the machine-
driven body. In its body, sensors and actuators are present in it. They are more flexible in terms
of performing new operations and is capable of carrying out numerous tasks at once. Recently
there is an emergence of technology branch with concerned of all the challenges in robot, design,
and application. Robots perform numerous activities such as defective satellite inspection, repair
or construction of a space station and supplying goods to the station and its retrieval. The paper
describes the design and implementation methodology used by the authors for developing tele
robotic system. There is high possibility of new advancement in robots with overlapping
knowledge in control and progress in fundamental technologies, kinematics and dynamics. This
will enable people to discover and familiarity in the universe with numerous live changes.
Technology in space has an important influence in both socioeconomic and life part
of space environment and the world society, therefore many study were carried out to help
combining robots and space through applying space robotics idea and some required of robotic
machines features are flexibility, acknowledgement, knowledgeable control and reconfigurable
methods. All imaginative decisions need to be tested and verified in open space condition
because aspect technology such as communication techniques cannot be verified on-ground
condition.

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METHODOLOGY
Control system Design Methodology
This section highlights the methodology used by the writer to design tele robotic
system. Each step is described in sequence as follows (Hermann, 2012, p. 410)
Hierarchy of desired behavior
The first step is to define and name a hierarchy of desired robot behaviors because it
is based on time-domain behavior. Usually, four steps are needed for autonomous submersible
and autonomous manipulator. The designer must ensure that the specified behaviors are enough
to allow description of all robotic system operations by personnel.
Level of Robot Autonomy
The robot requires less supervision as the hierarchy becomes automated. The decision
concerning the level of should be implemented based on complexity, safety, relationship between
channels of communication and required robot stability
Remote/local portioning
The machine-driven purposes can be alienated into remote [robot] and the local where
lower levels of control are executed by the robot more than the console.
Behavior matrix

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Before the execution of behavior by the operator at the work station and the robot,
certain things need to be defined such as requirements by sensory inputs to support the
decomposition, its nominal decomposition into lower levels and handling behavior execution,
Conflicting behavior resolution
The approaches such as the logic- based and cooperative are the preferred methods of
resolving conflicts goals. It is grounded on how robots are going to deal with the fact that they
are not intended to carry out other functions.
Control system modules
The communication associating the isolated computers is affected by computer error.
The robot are directed orders by the operator and the robots are expected to follow a systematic
protocol that are errors free while the response values from the robot to the operator can be
submitted repeatedly deprived of acknowledgment
Sera interface
It needs two types of definition levels;
 The standard real-time on-line operator interface and
 Scripting, configuration and behavior definition
Network of Software Modules
The designer needs to break down the system into a two-way communication between
the components and every component must be assigned preemption level.
Software module integration

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The real-time system is constructed from the existing components is just a
matter of selecting the required components from the library and explaining the interconnections
between them. The process of implementing the control system differs with software
components implementation
Declarative Configuration
This is where the user pronounces all components and their connections in a text built file then
the file is interpreted by the program after reading it so that it can modify the data structure for
real-time control.
Code-Based Configuration
This is the C++ version of declarative configuration approach whereby the configuration
file is gathered and joined before running of application
Graphical Configuration
This approach depends on the use of computer-aided design to put down the
components and their interconnections. The list is analyzed into a text-based in order to produce
a list describing the components and their interconnections.
Project management issues
The quality management, preparation of work and private issues are the matters affecting
project management and they are influenced by the design and implementation approach. This
approach task are partitioned into two parts that are the software component and control system
application whereby engineers specializing in application sector are responsible for application

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design, enactment and testing while the team in software are responsible for progress and upkeep
of all software constituents. (Robo, p. 211)
Ongoing Developments
This section describes the relevant developments taking place in design and
implementation of tele robot control system
SPACE ROBOT AREAS OF APPLICATION
Application of space robot can be classified into the following categories of
four; (Konoko, 2010, p. 318)
1. Operation: Helps to conduct experiment in the lab
2. Maintenance: Helps in removal and replacement of faulty modules/packages
3. In orbit positioning and assembly: Helps in deployment of satellite and
assembling of modules to satellite/ space station
4. Resupply: It enables supply of materials and equipment for experimentation in
space lab and for fuel resupply
The following examples give specific applications under the above categories
Scientific Experimentation
Experiments conducted in space lab include

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 Observations by astronauts
 Biological experiments
 Metallurgical experiments which sometimes is dangerous
Assist in space station assembly
 Helps crew in the space station i.e. routine crew maintain life supporting
system
 Helps in station arranging and assembling
Space servicing functions
 Refueling
 Faulty modules replacement
 Helps congested mechanism such as antenna and solar pane
Enhancement of space craft
 Using upgraded module in replacing payloads
 Assist in modules attachment in space
Space tug
 Transfer of satellites from low earth orbit to geostationary orbit
efficiently
 Effect orbital transfer by satellite grabbing

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Challenges in designing and testing space robot
Robots developed for space is different from those in the ground because
space robots have to operate in zero ‘g' conditions i.e. [lack of gravity], in the
vacuum, far away from earth and in high thermal gradients. (Xu, 2012, p.
32)Thermal condition and the vacuum of space interferes with material and
sensor performance of the robots. The degree of remoteness of the operator
varies from few meters to millions of kilometers
Zero ‘g’ effect on design
The environs that lack the force of gravity has strength and weaknesses. In
zero ‘g’ environment, the mass to be handled by the arm manipulator is not
constraints that is why joints and the arms of needs not to withstand forces and
moments loads as a result of gravity. The main disadvantage of zero ‘g’
environment is that it lacks inertial flame and any manipulator arm motion will
induce reaction forces and base moments which in turn interfere with the altitude
and position. (Kopa, 2011, p. 315)
The problems faced by the robot such as control and motion planning,
dynamics can be solved by ensuring dynamics connections between the base
[space station, space shuttle and satellite] and the robot. As a result of dynamic
interaction, the space robot motion can influence the base route and this can
make the robot to miss the planned target, also mutual dependence affects the

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performance of the robots and the base severely in case the moment of inertia
robot, the mass and payload are not negligible compared to the base. (Kanniah,
2013, p. 165)
Vacuum effect and thermal effect
The vacuum in space causes heat transfer problems and loss of mass of
the materials as a result of sublimation or evaporation. This can be avoided by
selecting materials and lubricants properly so as to attain collected unstable
condensable matter and total mass loss. The preferred lubricants should be dry in
nature like goad and lead. Some of the sub-systems will require hermetical
sealing in order to be exposed to vacuum.
In thermal variations, low-temperature cause material
embrittlement hence increases friction in bearing by weakening the adhesive
forces. The distortion in overcrowding of mechanism and structural elements is
caused by huge thermal gradients hence the best way of controlling this is
ensuring that proper material selection whose features is acceptable based on the
temperature range and suitable choice of protective coatings and insulation
system temperature is within permissible boundaries is carried out. (Desroches,
2010, p. 41)
Other factors
The compactness and the lightweight are one of the main factors
required in space system. The material structure to be used should possess certain

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strength and stiffness to ensure minimum mass, high toughness and solidity.
Robots are also subjected to a critical environment are the dynamics during
launch. Dynamic loads contain random vibration, auditory noise, sinusoidal
vibration and separation shock bands. The electronic and electrical subsystem
will have to take care of ecological conditions during orbit and launch. (Konoko,
2010, p. 78)
In case there is need for performance to be recorded, protection of
components against radiation all over its life is necessary to be considered.
Reliability of a high grade is required in space robots and this can be managed by
ensuring that design phase was conducted in a proper manner. In order to identify
numerous failure modes effects, a failure mode effect and critical analysis is
carried out and must be addressed in the design by (Kanniah, 2013, p. 179)
 Having a good design margin
 Selecting a reliable or proven design
 The design should have redundancy
RESULTS
System verification and testing

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System reliability is conducted by a number of tests enveloping all the
environmental conditions. The verification of tests and functions are carried out on
subassemblies, subsystem and tests acceptance will be done after system completion. The
trickiest simulation during testing will be zero ‘g’ simulation. The simulation commonly used in
zero (Kanniah, 2013, p. 89)
a) Water immersion: Total dipping of robots under water and testing helps in the simulation of
reduced gravity.
b) Flat floor test facility: Here, it is grounded on the bearing of air sliding over a polished
granite. It simulates the zero ‘g' environment in the parallel plane.
c) Compensation system: The compensation of force of gravity is done by vertical and
passive counter system and actively controlled parallel.
Performance assessment and calibration
The development of offline software in mission preparation helps in achieving the
robotic device operation. The procedures that supports design in a computer are applied so that
movement of the robot can be traced easily. The smallest size, mass and the power needed and
intake can be attained by ensuring an appropriate sensing technology is put in place. (Ruoff,
2011, p. 245)
Robot performance
The valuation of robot is needed because;
 To enhance sources of errors that affect arm accuracy

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 To make decision if the work cell or the arm must be calibrated
 To make the comparison on the expected improvement in calibration
accuracy.
The mathematical model is used in assessing the robot’s performance and the source of
error from its sub system such as the robot link, the joint or its gripper (Xu, 2012, p. 212).
Identification of error is done by a bottom-up analysis and in each identified robot sub system are
arranged in the three groupings namely;
 Pseud systematic error which is foreseeable and time variant
 Random errors which cannot be predicted but varies with time e.g. encoded noise
 The systematic error which does not differ with time e.g. concentricity, link length,
and parallelism.
Once the classification of error based on the magnitude is done, there may be used of
numerous statistical methods to evaluate its impacts when they are combined during work.
(Ruoff, 2011, p. 54)
Robot Calibration
A proper calibration method is required in compensate for errors in case the prediction
performance has shown that calibration is needed. All calibration must be carried out on the
ground and in case of orbit calibration procedures should be limited in crosschecking the model
validity developed and if essential, error correction such as pressure gradient and micro slip to be
done. Calibration is executed in five steps namely; (Genta, 2011, p. 33)