library(readxl, quietly=TRUE)
df <- read_excel("d:/my.xlsx",col_names = TRUE)

library(RPostgreSQL)
drv <- dbDriver("PostgreSQL")
con <- dbConnect(drv, user='postgres', password='', dbname='alitrack', host='postgres.alitrack.com')

postgresqlpqExec(con, "SET client_encoding = 'GBK'")

dbWriteTable(con, c("my_schema","my_table"), data.frame(df), row.names = FALSE)
# Free up resources
dbDisconnect(con)
dbUnloadDriver(drv)