The current success rate of CubeSat missions, particularly for first-time developers, may discourage non-profit organizations to start new projects. CubeSat development teams may not be able to dedicate the resources that are necessary to maintain Quality Assurance as it is performed for the reliable conventional satellite projects. This paper discusses the structured life-cycle of a CubeSat project, using as a reference the authors’ recent experience of developing and operating a 2U CubeSat, called qbee50-LTU-OC, as part of the QB50 mission. This paper also provides a critique of some of the current poor practices and methodologies while carrying out CubeSat projects.
This paper presents a new dynamic formulation as well as control scheme for space manipulators in order to drive the end-effector along a desired trajectory while minimizing the base disturbances caused by the arm movements. Through the new dynamic formulation, the end-effector is viewed as a Virtual Base, and the end-effector variables are also considered as generalized coordinates. As a result, joint controllers can be designed without having to solve for the inverse kinematics problem and computing the derivative of the generalized Jacobian matrix. Consequently, the joint control torque can be obtained analytically through the Lagrange multipliers method. Further, the joint control torque is also obtained through a quadratic programming problem in order to take into account the joint torque constraints. Several case studies are simulated to demonstrate the new control scheme and compare its performance with that of other controllers.
Hardware-in-the-loop simulation is an increasingly popular engineering tool for its effectiveness in maintaining a balance between the two competing demands of: a) well designed and thoroughly tested systems, and b) reduced development time and costs to remain competitive. This paper proposes an architecture for applying hardware-in-the-loop simulation techniques to the design and testing of robot manipulators. Potential benefits of this architecture include allowing concurrent development of hardware and control system components and providing a reusable platform for reconfigurable manipulators through a generic and modular structure. An implementation of this architecture in the preliminary phases of development is presented here to demonstrate how these benefits can be realized
Reconfigurable Manipulators are structurally redundant robots that utilize a subset of their joints to perform a specific task optimally. This paper presents a method of finding a task-based optimal configuration for a new type of reconfigurable robot manipulator, called the modular autonomously reconfigurable serial (MARS) manipulator. The reconfiguration optimization treats the joint space of the MARS manipulator as a 12-dimensional smooth configuration manifold. The manifold is discretized and ranked based on a variety of criteria, and then clustered into attractive and repellent regions. The user then specifies which regions are desired in the target configuration, and the manifold is reduced in dimension in order to maximize the number of attractive regions and minimize the number of repellent regions. Six manipulator configurations are synthesized using this approach, and their effectiveness is compared.