Virtual walking in virtual environments (VEs) requires locomotion interfaces, especially when the available physical environment is smaller than the virtual space due to virtual reality facilities limitations; many navigation approaches have been proposed according to different input conditions, target selection and speed selection. With current technologies, the virtual locomotion speed for most VR systems relies primarily on rate-control devices (e.g., joystick). The user has to manage manual adaptation of the speed, based on the size of the VE and personal preferences. However, this method cannot provide optimal speeds for locomotion as the user tends to change the speed involuntarily due to non-desired issues including collisions or simulator sickness; in this case, the user may have to adjust the speed frequently and unsmoothly, worsening the situation. Therefore, we designed a motion protector that can be embedded into the locomotion system to provide optimal speed profiles. The optimization process aims at minimizing the total jerk when the user translates from an initial position to a target, which is a common rule of the human motion model. In addition to minimization, we put constraints on speed, acceleration and jerk so that they do not exceed specific thresholds. The speed protector is formulated mathematically and solved analytically in order to provide a smooth navigation experience with a minimum jerk of trajectory. The assessment of the speed protector was conducted in a user study measuring user experience with a simulator sickness questionnaire, event-related skin conductance responses (ER-SCR), and a NASA-TLX questionnaire, showing that the designed speed protector can provide more natural and comfortable user experience with appropriate acceleration and jerk as it avoids abrupt speed profiles.

在虚拟环境（VE）中进行虚拟行走需要移动接口，尤其是在由于虚拟现实设施的限制而使可用物理环境小于虚拟空间时；根据不同的输入条件，目标选择和速度选择，已经提出了许多导航方法。使用当前技术，大多数VR系统的虚拟运动速度主要依赖于速率控制设备（例如，操纵杆）。用户必须根据VE的大小和个人喜好来管理速度的手动调整。但是，这种方法不能为运动提供最佳速度，因为用户会由于诸如碰撞或模拟器疾病等不希望的问题而自愿改变速度。在这种情况下，用户可能不得不频繁且不平稳地调整速度，情况恶化。因此，我们设计了一种运动保护器，可以将其嵌入到运动系统中以提供最佳的速度曲线。优化过程旨在使用户从初始位置平移到目标时的总跳动最小，这是人体运动模型的普遍规则。除了最小化之外，我们还对速度，加速度和加速度率设置了限制，以使它们不超过特定阈值。速度保护器是通过数学方式制定的，并且可以通过解析方式求解，从而以最小的移动轨迹提供流畅的导航体验。速度保护器的评估是在一项用户研究中进行的，该研究使用模拟器疾病问卷，事件相关的皮肤电导反应（ER-SCR）和NASA-TLX问卷来测量用户体验，