Xiao, "Mechanical design of a compact Serial Variable Stiffness Actuator (SVSA) based on lever mechanism," in Proceedings of the 2017 IEEE International Conference on Robotics and Automation (ICRA), pp.
Caption: Figure 1: CAD model (a), prototype (b), and schematic model (c) of the SVSA.
Serial-type VSAs (SVSAs) do not have this requirement and have gained more attention.
This paper focuses on modeling and control of a class of SVSAs based on level mechanisms.
By considering gravity and external loads, the dynamic model of SVSAs is represented as follows:
The dynamic model of SVSAs given by (1)-(5) can be represented in the standard form
A general specification of SVSAs in Table 1  is used for simulation.
A tracking task with the desired position [q.sub.d](t) = 120 sin(pi]t) ([degrees]) and the desired stiffness [[sigma].sub.d](t) = 50 sin(1.25[pi]+ [pi]) + 55 (Nm/rad) (frequency 0.5 Hz) is chosen to show the tracking performance of the proposed controller for SVSAs, where the desired stiffness [[sigma].sub.d] ranges between 5 and 105 Nm/ rad.
After the device has passed Endpoint Integrity Verification, SVSA creates and launches a Secure Virtual Desktop Environment.
When the session is terminated or the configurable inactivity timeout period is met, SVSA will sanitize the system by removing all data that was downloaded or created in the Virtual Desktop Environment including file downloads, configuration changes, cached browser information, password entered, and auto-complete information.
SVSA has the ability to transparently adapt policies based on identification of network locations and the type of network device (corporate owned vs.