Abstract-Gait event detection is important for intent predication in lower limb prostheses and exoskeletons during different activities. Human gait cycle is divided into two main phases i.e. swing phase and stance phase. Initial contact (IC) with the ground indicate the start of stance phase while Toe Off (TO) is the start of swing phase. This article presents algorithm based on set of heuristic rules for gait event detection using a single gyroscope attached on shank of subjects performing activities of daily living such as normal walking, fast walking, ramp ascending and ramp descending. The algorithm sequentially detected gait events like IC, TO, Midswing (MSw) and Midstance (MSt). Results were compared with the reference pressure measurement system using Flexiforce footswitches (FSW). The mean difference error between the reference and proposed system was for IC is about +4ms and for TO is about -6.5ms. The results showed that proposed algorithm achieved high detection performance compared to the existing algorithms and will lead to powerful tool to develop an intent recognition system for lower limb amputees.
I. INTRODUCTIONLocomotion is crucial for human during activities of daily living (ADLs) as it plays an important role in gait efficiency and task progression. Patients with pathologic gait suffer from higher energy consumption and risk of falls. Gait analysis and event detection has been used in different applications using ambulatory gait systems to evaluate and improve patients' motilities and to control the functional electrical stimulation (FES) [1][2][3].Gait events can be detected using either force based measurement systems by means of footswitches such as force sensitive resistors (FSR) [4], or wearable sensor such as Inertia Measurement Unit (IMU) [5]. To perform outdoor activities for longer period of time, it is crucial to use the systems which are reliable, portable, small, inexpensive, and with low power consumption [6][7][8].Many researchers have used wearable sensors (accelerometers and gyroscopes) for analysis of spatiotemporal gait parameters during ADLs [9,[20][21]. Gyroscopes have been applied for detecting the gait events for triggering [10] amputees [20]. Locating the gyroscope on shank has many advantages as opposed to other parts of the human body [12], such as less soft tissue muscles at shank compared to thigh. In addition, gyroscope placed at shank is acceptable accurately in healthy and pathological subjects [13,14].Sabatini et al.[15] developed a gait event detection system for analysis of incline walking based on a single gyroscope attached on the foot of healthy subjects. However, placing gyroscope on shank provides ease of use as compared to its placement on foot as it provides less signal variability between the subjects. P. Catalfamo et al.[16] used a single gyroscope placed on the shank for detection of initial contact (IC) and foot off (FO) in subjects walking up and down on inclined surface and level ground. The results were compared with a reference system of foot ...