We present BERTiMuS, an approach that uses CodeBERT to generate mutants for Simulink models. BERTiMuS converts Simulink models into textual representations, masks tokens from the derived text, and uses CodeBERT to predict the masked tokens. Simulink mutants are obtained by replacing the masked tokens with predictions from CodeBERT. We evaluate BERTiMuS using Simulink models from an industrial benchmark, and compare it with FIM – a state-of-the-art mutation tool for Simulink. We show that, relying exclusively on CodeBERT, BERTiMuS can generate the block-based Simulink mutation patterns documented in the literature. Further, our results indicate that: (a) BERTiMuS is complementary to FIM, and (b) when one considers a requirements-aware notion of mutation testing, BERTiMuS outperforms FIM.

As an indispensable part of future sixth generation (6G) wireless communication, unmanned aerial vehicle (UAV) communication has become an inevitable trend and developed rapidly. The channel emulator is an effective and resource-saving tool to evaluate the designed UAV communication systems. In this paper, a novel UAV multi-trajectory dual-mobility channel model is proposed. Then, based on the Coordinate Rotation Digital Computer (CORDIC) method, the hardware implementation of the proposed model is developed in the Field Programmable Gate Array (FPGA). As the hardware output data of channel emulator, the channel impulse responses (CIRs) are acquired. Furthermore, the corresponding power delay profile (PDP) and root-mean-square (RMS) delay spread calculated by the CIRs are analyzed. Finally, by comparing with the simulation results of proposed channel model, the availability and accuracy of the channel emulator is validated.

To enrich legged robots with fast energy-efficient mobility on even terrain, wheeled-legged robots have emerged as a valued robot form in robotics research. This paper describes the complete development of a new wheeled-legged quadruped robot named Max, ranging from its mechanical design over system architecture to core algorithms implemented for it to realize various motion behaviors. Instead of attaching wheels to the distal ends of legs as in the existing wheeled-legged robot designs, this robot has wheels installed on the knees with a special switching mechanism to convert a leg between the legged and wheeled locomotion modes. This design keeps the wheeled leg lightweight, enabling the robot to preserve the motion agility as a quadruped robot while gaining the energy-efficiency as a four-wheel or even two-wheel mobile robot. An online locomotion generation method is proposed to compute the 6-D body trajectory of the robot in walking on the perceived terrain, while dynamic movements such as leaps and flips are generated by a unified trajectory optimizer, which is also used to generate the transition motions of the robot to transform into the wheeled mode. The diverse mobility of the proposed robot Max is verified with extensive experiments.Note to Practitioners—Empowering robots with all-terrain mobility is a fundamental open problem in developing a new generation of robots. To this end, combinations of wheels and legs have been explored for robots to possess both traversability on uneven terrains and efficiency on even terrains. This paper proposes a new wheeled-legged quadruped robot with focuses on the integrated design of wheeled legs, system architecture, and core algorithms implemented for various legged and wheeled locomotion behaviors. To embed wheels without adding additional motors and keep the light weight of original legs, a special switching mechanism is designed and integrated at the knee joints where wheels are installed. Algorithms for generating quadrupedal walk according to online perceived terrain information as well as other dynamic legged and wheeled motions are discussed and demonstrated. The system architecture for allocating all vision and motion algorithms is also presented. This work is intended to provide a whole picture of developing this new robot including both hardware and software aspects.

The wheel-bipedal robot has the advantages of both wheeled robots and legged robots, but as a cost, it is more challenging to perform flexible movements in various surroundings while keeping it balanced. The inaccurate dynamics of the robot makes the balance problem even more intractable. To solve this problem, the robot Ollie is used as a testbed. The whole-body control (WBC) framework is adopted to enhance the dexterity of the robot with multiple degrees of freedom in the task space. Moreover, a learning-based adaptive technique is applied to assist the WBC such that the balance controller can be designed in the absence of the accurate dynamics. Physical experiments demonstrate that the robot can manage various actions, with the help of the combination of the WBC and the learning-based adaptive technique.

This paper presents a balance control technique for a novel wheel-legged robot. We first derive a dynamic model of the robot and then apply a linear feedback controller based on output regulation and linear quadratic regulator (LQR) methods to maintain the standing of the robot on the ground without moving backward and forward mightily. To take into account nonlinearities of the model and obtain a large domain of stability, a nonlinear controller based on the interconnection and damping assignment - passivity-based control (IDA-PBC) method is exploited to control the robot in more general scenarios. Physical experiments are performed with various control tasks. Experimental results demonstrate that the proposed linear output regulator can maintain the standing of the robot, while the proposed nonlinear controller can balance the robot under an initial starting angle far away from the equilibrium point, or under a changing robot height.