Risk-Incorporated Trajectory Prediction to Prevent Contact Collisions on Construction Sites

Abstract

Many construction projects involve a plethora of safety-related problems that can cause loss of productivity, diminished revenue, time overruns, and legal challenges. Incorporating data collection and analytics methods can help overcome the root causes of many such problems. However, in a dynamic construction workplace collecting data from a large number of resources is not a trivial task and can be costly, while many contractors lack the motivation to incorporate technology in their activities. In this research, an Android-based mobile application, Preemptive Construction Site Safety (PCS2) is developed and tested for real-time location tracking, trajectory prediction, and prevention of potential collisions between workers and site hazards. PCS2 uses ubiquitous mobile technology (smartphones) for positional data collection, and a robust trajectory prediction technique that couples hidden Markov model (HMM) with risk-taking behavior modeling. The effectiveness of PCS2 is evaluated in field experiments where impending collisions are predicted and safety alerts are generated with enough lead time for the user. With further improvement in interface design and underlying mathematical models, PCS2 will have practical benefits in large scale multi-agent construction worksites by significantly reducing the likelihood of proximity-related accidents between workers and equipment.

FIGURE I FOUR PRIMARY CAUSES OF CONSTRUCTION WORKER FATALITIES

FIGURE II EQUIPMENT MOVEMENT DIRECTION WHEN ACCIDENT OCCURS (N=594)

FIGURE III MAIN STEPS OF THE DEVELOPED HMM-BASED TRAJECTORYPREDICTION METHOD

FIGURE IV KEY ELEMENTS OF HMM PREDICTION MODEL

FIGURE V INPUT-PROCESS-OUTPUT DIAGRAM OF HMM TRAINING STAGE

FIGURE VI INPUT-PROCESS-OUTPUT DIAGRAM OF HMM PREDICTION STAGE

FIGURE VII VARIATION OF ANGULAR RISK FACTOR (α) NEAR THE HAZARD ZONE

FIGURE VIII LINEAR RISK FACTOR AND ADJUSTMENT OF PREDICTION

FIGURE IX HIGH-LEVEL FLOWCHART OF PCS2 MOBILE APPLICATION

FIGURE X SCREENSHOTS OF THE PCS2 MOBILE APPLICATION LAYOUTS

FIGURE XI FUNCTIONS USED FOR ALERT USERS FROM THEIR LOCATION DATA

FIGURE XII INITIAL INPUTS OF PCS2 FOR THE FIELD EXPERIMENT

FIGURE XIII EXPERIMENT SETUP WITH THE FORKLIFT AS A SITE HAZARD

FIGURE XIV COLLECTED USER TRAJECTORY IN THE VICINITY OF THE FORKLIFT

FIGURE XV USER APPROACHING A HAZARD ZONE DURING THE FIELD EXPERIMENT

TABLE I RESULTS OF PCS2 FIELD TEST

TABLE II technological breakthroughs, the real value of mobile RECALL, PRECISION, AND ACCURACY OF THE FIELD TEST